The fuck... I can't believe what I've just read. That's like saying Newton set us back over a hundred years.
There was no regression because of Einstein.
Mainstream theories are so good that they dwarfed competition. Lack of competition caused lack of progress. It was easy to collect hundreds of downvotes on HN just by talking about alternative theories or about physical representation of abstract theories. Now such comments will collect mere dozens of downvotes. It also should be obvious that a new successful theory will account for more things, so it will be much more complex than previous theories.
Yeah, um... if you're going to claim something like that, you need more than the claim. What evidence do you see for your position? What evidence can you give us so that we can evaluate your position?