> This is exactly the problem - early on there was a lot of "low hanging fruit" in science - entire new areas where our tools and capabilities for discovery and analysis got way better very quickly. Think of everything that better telescopes, scanning electron microscopy, and computerization allowed.

This trope gets repeated every so often but it's just a trope. In 1900s people felt all physics was solved, then came relativity and the photoelectric effect. In the 1940s, after the second world war, atomics was the ultimate of physics, then we developed transistors. Until 1950s, sand was basically a worthless resource, and now, good quality silica commands a high price in the global marketplace. Truth is, there are many low-hanging fruit, we cannot even guess what we don't know when we don't know it. I wager that we have barely scratched the surface of what is possible.

It's still possible to make ground-breaking innovations. In fact, they come with regularity, along with all the pulp that qualifies as research nowadays. Here's an example from my field: https://www.cs.cmu.edu/~odonnell/hits09/gentry-homomorphic-e...