In my organization we have RFCs, PRDs, ADRs etc. and I would say that the process is fairly broken. That said, I think what you mention is an important but not the only failure mode of a proposals process.

In some cases I have seen, people use RFCs to steamroll decisions when they are the only stakeholders. Here the waste comes from the fact that the proposal becomes just a bureaucratic step or a way to diffuse responsibility.

In the case you mention (which I have seen many times) I would say the general issue is that the goals and the constraints are not qualified sufficiently. If that's the case, then there are only 2 cases: there is an objective way to measure if an objection or comment makes sense or not, or it is subjective. If it's objective, then consensus is easy to reach, if it's subjective, it needs to be acknowledged and usually the decisions falls on those who are responsible for the outcome (e.g., the team who needs to maintain or build the thing).

Of course, the debate can move to constraints, goals or even ways to measure, but these are generally more straightforward.