As with all things - both are probably true.

It might be that we attribute post hoc greatness to a small number of folks, but require a lot of very interested / ambitious folks to find the most useful threads to pull, run the labs, catalog data, etc.

It's only after the fact that we go back and say "hey this was really useful". If only we knew ahead of time that Calculus and "tracking stars" would lead to so many useful discoveries!