Mostly experience (based on being a PhD scientist, a postdoc, a National Lab scientist, and engineer at several bigtech companies), partly speculation (none of the groups/labs I worked in operated at "the highest level", but I worked adjacent to many of those).
I'm pretty sure most image fraud went completely unrealized even in the case of replication failure. It looks like (pre AI) it was mostly a few folks who did it as a hobby, unrelated to their regular jobs/replication work.
In most of the labs I've worked in replication is not a common task[0]
Part of my point is that being unable to publish replication efforts means we don't reduce ambiguity in the original experiments. I was taught that I should write a paper well enough that a PhD student (rather than candidate) should be able to reproduce the work. IME replication failures are often explained with "well I must be doing something wrong." A reasonable conclusion, but even if true the conclusion is that the original explanation was insufficiently clear. I'm sorry, didn't you say Because your current statement seems to completely contradict your previous one.Or are you suggesting that the groups you didn't work with (and are thus speculating) are the ones who replicate works and the ones you did work with "just trust their competitor's competence")? Because if this is what you're saying then I do not think this "mostly" matches your experience. That your experience more closely matches my own.
[0] I should take that back. I started in physics (undergrad) and went to CS for grad. Replication could often be de facto in physics, as it was a necessary step towards progress. You often couldn't improve an idea without understanding/replicating it (both theoretical and experimental). But my experience in CS, including at national labs, was that people didn't even run the code. Even when code was provided as part of reviewing artifacts I found that my fellow reviewers often didn't even look at it, let alone run it... This was common at tier 1 conferences mind you... I only knew one other person that consistently ran code.