I'm only in High School and my PhD is still a far away dream for me, but I think I can sort of understand what your saying. I've asked myself the question of if I'd ever truly do anything great and win a Nobel Prize and be remembered and all that. My answer to that is that all science no matter how much it's been researched in the past or weather it's new research or not doesn't really matter. Science is a big loop with no end, so it's the journey that matters. It's about doing the science and learning new things whether they were known before or not. I recently scrapped a lofty project trying to revolutionize clean energy. It was futile from the start and secretly I knew that, but I kept going and with that I learned more than I did in school, and that will stay with me forever. I'm sorry for rambling on like this. I'm very good at that, but I'll close with this statement that I truly believe. We don't need to revolutionize science. As long as keep learning, keep exploring, and question everything in a big way, anyone big and small is just as great as Tesla, Newton, or even Einstein.