>.. there are many things that are complex and can't be made simpler without destroying the functionality of the program.

This is because we haven't figured out how to make them simple yet. I believe all problems can be made simple, once we come up with the proper system. Maybe we don't have the correct abstractions yet or just haven't figured out the best data layout. We've only been collectively programming for a few years now I think we have plenty of room left to advance the field. I'm not ready to just throw in the towel and say impossible.