[Maro]

"SR similarly wasn't required to explain anything important"

I don't agree. The Maxwell equations (1865-1875) already implicitly encode the Lorentz transformation as the symmetry group, that's one of those "sooner or later somebody would have come along and put a spacetime theory behind it" thing, in this sense it's not up there with Newton. As you probably know there were a bunch of physicists who were looking at this (eg. Lorentz, Poincare, Larmor, etc). Then it was Einstein who tied it all together, and it was called the Special Theory of Relativity. (But this is one of those cases where this was going to happen anyway.)

I agree that Einstein was able to borrow manifolds and tensor calculus from the mathematicians, unlike Newton, who had to invent everything.

Btw. this is a great discussion.