“Just” is good…what you want is still one of the most complex things in computer graphic history. Some things are definitely possible, but they need an insane amount of people working on them because its basically brute force Nobody has done it before, so everybody is just running around like crazy and tries everything he can imagine to make it somehow work^^ For example, and sorry I will probably say some things wrong because I dont remember the exact details, but it should give you an impression. When we talked about the 90 render guys from DICE and Battlefront at the office, my friend said that they had to do an insane amount of trial and error testing on how to optimize the use of compute shaders since there are apparently no tools for it. So they had teams (!!) of graphic programmers dedicated to just one little task, one small bit of the renderer, and they tested hundreds of different configurations over all platforms until they found the sweet spot for each of them. That took an insane amount of time and yes, in the end they were able to make **** run that normally wouldnt, but you have to have the people, the time and the money to do . Also…sometimes those things can even have a greater effect on a production than you imagine in the beginning. They wanted for example to have all clothing physicalized. After they moved that whole physics stuff over to compute shaders and did their black magic, they found out that method only performs well if there are no vertices with more that 3 edges to it. So yeah…character department started building characters before that was clear, so in the end they had to redo (or retopologize) ALL character from the game to make sure they work with these specifications.
Anyway…long story short…yeah tech advances etc…but it also gets so much more complicated and time consuming to squeeze every bit out of it. Its really hard and takes a lot of effort. And I know I would like what you said as well…like really really badly! But I also know how hard it is to do and Epic doesnt make an engine specific to one game and platform. So there is that as well
Cheers!