Ok, I actually have an answer on that, but if I tried to thoroughly explain it would get extremely long, so I will try to keep it short but offer a few things to look up that will help you understand my point of view.
Short answer is yes, people in ancient times used to be able to perceive metaphysical phenomena more easily than we can now. There are a few factors that contribute to this. One is the fact that nowadays there's too much electromagnetic pollution that is blocking people (look up Faraday cages to see what happens to non psychic people when something insulates them from elecromagnetic pollution, to see what I mean).
Another factor is the extreme number of stimuli and the speed of modern life compared to that of previous ages. It has been suggested that in modern times the long periods of isolation and devotion to prayer to reach the altered states needed for successful spirit contact during evocation can be shortened, because due to the stimuli in modern times being infinitely more, locking yourself in a cabin in the middle of nowhere for the weekend will get you to that state, whereas in the 15th century for example your normal state of life and the one you aimed for for the ritual weren't that far different, so you had to spend 40 days for example to get to that state gradually). What the isolation does is remove the stimuli to open the way for your other senses to kick in unobstructed, so it can happen much faster in our age, to the point that many people find themselves unable to cope with a weekend all alone in the woods without a phone, TV, radio, traffic noises etc because they start getting delusional (see the connection there? They start seeing things that weren't supposed to be there, so they automatically assume this must not be real, they are having psychological issues) or have panic attacks.
A third factor is a difference in our dominant model of interpreting the world. I have touched on that subject before, when I posted about how people tend to grad the beliefs and worldview of their old religion into the new one, because they don't realize that the model of interpreting the world isn't the only one that exists. Switching models gives you a whole different world essentially. I know it sounds crazy if you haven't personally experienced it, but it truly does. And this is important because your dominant model of how things work determine what is real and what is not for your brain. Whatever you perceive as reality goes through your brain and is interpreted in a way that makes sense. So if you are operating within a model that isn't conducive to spiritual activity, that stimuli will be automatically removed by your brain, in an attempt to maintain coherence. If you grow up believing that the tree on the hill and the river are non-human people, then you have far higher chances of hearing them talking to you than if you believe that they are not alive, or that they have no spirit that can talk to you. And if you can talk with the plants, then you can talk with demons and other spirits too. For an illustration of what I mean, try watching documentaries or reading anthropological studies on first contact nations and observe how their approach to the world around them is very different to what the western world's approach is. There's also an essay on Gordon White's (overall excellent book)
Pieces of Eight on different models of interpreting the world, that might help.
Now this is a very important consideration, because even today you can compare different countries and notice that in some places, there are infinitely more reports of paranormal activity and miraculous magic than in others. And this always goes hand in hand with the dominant interpretation of the world the people there have, and how much this includes or prohibits the existence of such phenomena. If you notice, in most stories of someone who wasn't at all a believer experiencing something paranormal very directly, these people had the experience away from home, and often when visiting a place where people see the paranormal as something real, as part of their normal lives. Which also shows that if you haven't had such experiences in your life that would make you see them are truly real, and if you have grown up in a place where they aren't seen as real, or even acknowledged in any way, then you are far more likely to have such an experience away from your familiar environment (and preferably someplace your brain considers exotic) than at home, out of the blue, when it has never happened to you in your whole life. Cause if it happens at home, your brain is most likely to edit it out because it makes no sense to what it knows as real and normal (for the brain editing out stuff part, do a search for cars crashing on airplanes that had to perform an emergency landing on the highway. Drivers almost always report not seeing a plane or anything else for that matter, until after they crushed on it. That's cause a plane in the middle of your usual route to work is so unlikely, that your brain literally edits the image of the plane out. That's exactly how your brain would edit the visual of a spirit manifesting to you out).
Last point I wanted to make is that even in ancient times, not everybody could easily communicate with spirits. Shamans could. And they 1) went through a long initiation where they had to learn everything the spirits wanted of them or perish, and 2) they used drugs, and other extreme mind-altering methods to establish communication. Including ritual torture and poisoning themselves to half-cross over to the other side.
Regarding suggestions, beside shifting into a different model of seeing the world (which I'd highly recommend), I would recommend entheogens, with the best possible scenario being an ayahuasca retreat or something similar, performed with the help of an authentic shaman and not one of the mainstream retreats that are popular among tourists lately just for the kicks of it, and preferably going to the place where such ceremonies are perform (again, instead of a retreat just outside the city where you live, for the added benefit of the very different environment that allows your brain the leeway to perceive more things as real than it usually does). This is often what kickstarts people into being able to perceive spirits and converse with them. The other suggestion (probably easier and cheaper) would be mushrooms. I know many people who either had been trying for years without any results and one of these two things was what did it for them and a whole new world opened up to them, or they had some ability, but after the experience with one or both of these two, they had a significant increase in ability, describing it as something being unlocked in their brain that stayed open after the experience, allowing them to perceive more than they were able to.*
A more meditative-based suggestion is Inner Heat practice. Jason Miller's book
Sex, Sorcery And Spirit has detailed instructions on Inner Heat practice and how to do it safely without initiation or teacher (it can be dangerous if performed the wrong way and without a teacher).
I think this covers most of what I had in mind. Believe it or not, this actually is the very short version, lol!!
*For the record, I am not suggesting that anyone engage in practices or use substances that may be dangerous to them, or that are illegal where they live. I don't personally use drugs of any kind, but I never had extreme difficulty interacting with the spirit world. My suggestions are based on the experiences of people I know, not on my own personal experience, and are should only be considered by adults who are fully responsible for their own decisions, and who can fully grasp the possible dangers and have knowledge of whether the use of such substances is legal where they live or not.