I agree entirely. The more tendency there is to push development as an "engineering" discipline, the more evidence based research needs to be used to solidify or disprove certain development dogmas repeated over and over again, which in many cases, seemingly have no empirical evidence beyond a few anecdotal success cases.

This is the norm in the industry, "you're doing it wrong, the best way is this way..."--based on what evidence that pertains to this case or has proven generalized success applicable here?

In most cases, it's someone's successful anecdotal experiences which worked for the specific cases they were involved with. That doesn't mean those approaches can be abstracted away and generalized to all cases, but many in this industry do that regularly and critique others' approaches based on that. It becomes this competitive ego contest: well my work was at x, y, z solving q and was successful--making me an authority on a, b, c's problems solving p because x, y, z is a leader (appeal to authority fallacy)... etc.

It's one thing to treat development as much of an art (which to me, it very well still is) but once you start treating it as a concrete discipline, you need to provide the lyme, cement, aggregates, water... evidence and studies showing approaches and how they faired across controls and varied cases.