Talking about frontier mathematics? Even the common for-mere-mortals version of mathematics is totally inaccessible to most people. Even to those who want to really learn it.
Take a good look at the textbooks that teach mathematics and tell me I am wrong.
There are many amazing Youtube channels that explain complex math well, for example https://www.youtube.com/c/3blue1brown
The books exist and are possible to understand. They teach maths at most universities. You should try it, learning is fun.
If there is any barrier, it is not intentional, I assure you. Math is just hard.