>... unless I see some kind of evidence of the contrary

That's easy. Watch Netflix.

>... my default assumption is that these people are competent at the jobs.

Have you met people? Personally, I look at low odds of getting a group of competent ones together at the same place, and use the default assumption that at one point they were less incompetent than their competitors and that momentum can keep things going for a long time after that is no longer true.