The reason for your second paragraph is pretty straightforward. There has been an immense amount of support for proteins as "the workhorses of the cell" for hundred+ years. I call it the "protein bias". We've seen in many times- for example when it was first hypothesized and then proved that DNA, rather than protein, is the heredity-encoding material, and seen many times, for example in the denial that RNA could act as an enzyme or the functional core of the ribosome could be a ribozyme.

I think what basically happened is a very influential group of scientists mainly in Cambridge around the 50s and 60s convinced everytbody that reductionist molecular biology would be able to crystallize proteins and "understand precisely how they function" by inspecting the structures carefully enough.

I learned, after reading all those breathless papers about individual structures and how they explain the function of protein is that in the vast majority of cases, they don't have enough data to speculate responsibility about the behavior of proteins and how they implement their functions. There are definiteyl cases of where an elucidated structure immediately led to an improved understanding of function:

"It has not escaped our notice (12) that the specific pairing we have postulated immediately suggests a possible copying mechanism for the genetic material."

but most papers about how cytochrome "works" aren't really illuminating at all.