It's very seldom in science that both happens at exactly the same time.

Interesting.

I imagined a world where Wegener appeared, out of blue, with all that data about geological strata and fossils (nobody noticed any of that before), and declared that it's all because of continental drift. That was anticlimactic and unsatisfactory.

I imagined a world with a great unsolved mystery: all that data about geological strata and fossils. For a century, nobody is unable to explain it. Then Wegener appeared, and pointed that the shapes of continents are similar, and perhaps it's all because of continental drift. That was more satisfactory, and I suspect that most of traces of disappointment are due to hindsight bias.

I think that there are several factors causing that:

1) Story-mode thinking

2) Suspicions concerning the unknown person claiming to solve the problem nobody has ever heard of.

3) (now it's my working hypothesis) The idea that some phenomena are and 'hard' to reduce, and some are 'easy':

I know that fall of apple can be explained in terms of atoms, reduced to the fundamental interactions. Most of things can. I know that we are unable to explain fundamental interactions yet, so equations-without-understanding are justified.

So, if I learn about some strange phenomenon, I believe that it can be easily explained in terms of atoms. Now suppose that it turned out to be very hard problem, and nobody managed to reduce it to something more fundamental. Now I feel that I should be satisfied with bare equations because making something more is hard. Maybe a century later.

This isn't complete explanation, but it feels like a step in the right direction.