The biggest reason is that phycisist arent encouraged to persue big ideas. Funding is usually given to people with a set goal; some sort of application of settled science. There is little funding for the kind of ideas that Einstein went after. Now-a-days Einstein would have likely been caught up in bureaucracy, trying to get funding just to deviate slightly from "established fields". He likely wouldn't have made as big an impact.

There's also the problem with "our generation". In my experience, fundamental research isn't as "sexy". Most of it is boring. If you give a fundamentals talk at a conference, you really have to try hard to keep people interested. Younger researchers tend to be more interested in building new technology. Applying new scientific ideas, instead of finding them.

And then there's computers.

We're also still going off of the "computer boom". Instead of making new theories for how (say) electromagnetism works, we are still exploring the solutions of Maxwell's equations that are now available to us because of computers. Think about it. We can solve Maxwell's Equations for an infinite number of systems!!! Einstein didn't have that ability.

Though this computational boom we made some cool discoveries that likely flew under the radar because, again, they are based on old Equations. Arguably the entire fields of photonics and nanophotonics (my fields) were built off of our ability to solve more difficult electromagnetic problems using computers.

But is this a bad thing?

Computers make the barrier of entry lower. You don't have to be a genius to be a theoretical phycisist. You really only need a decent education, and a love for code (and maybe some math). It's how I got my job. Anybody with an above average intelligence could become a phycisist now. That means that we can make more (smaller) discoveries and have fun doing it.