Most people take issue with the repetition of similar tests and evaluations for multiple companies. If A, B, and C were considered different stages of a technical interview, candidates are repeating A and B too often, whereas applying A and B once would suffice for several companies.
It's a problem that is realized when opportunity cost is compounded when interviewing multiple companies and it's not something that a single company alone can fix. A more "Docker-ish" solution where using one of "A" to lay the foundation for many company interviews (and not just the ones expecting you to practice Leetcode) might curtail the problem of using more time and resources than necessary.
But more than that, there is also a cognitive dissonance with the beliefs of how to reform a broken system. Programmers largely oppose industry-wide regulation while also expecting the vetting process to be more consistent and make more sense. This is a tough nut to crack because we seemingly want to have it both ways.