As a onetrick, I used to be super angry that Autofill and secondary roles are a thing. I still do dislike autofill, and I've moved onto a retirement life in ARAM because my luck with getting roles in ranked isn't stellar. At this point, though, it's been far too many years into this game for me to care either way. I really only want someone to help me understand the logics behind Riot's decision. It just bugs me that I never understood why they did what they did, bcuz not being able to figure it out makes me feel stupid.
1. If it's truly an overwhelming majority of players in this game who are willing to give up their favored roles to lower queue time, then there should be no point in forcing autofill upon absolutely everyone. Only a handful of people will be sitting in queue and waiting for hours, right? That's not gonna impact the queue time of everyone else by too much. It's would be like going from having 20k people in queue at once, to 19.5. The difference is not even statistically significant. In this situation, Riot is only ruining the game for a small number of players, but they're doing it for absolutely no reason whatsoever. Why alienate the people who can only perform in one role, when it doesn't even do anything to help the rest of the community? It's not like Riot can make money by forcing them to quit the game.
2. If autofill *is* a dividing issue, and if giving people the choice to not autofill will drastically increase the queue time of everyone else, then it's an even worse idea to just force autofill onto the whole playerbase. It would take a lot of people actively opting out of autofill to effect the queue time of those who do autofill in any meaningful way. If that is going to be the case, though, then it means that a big chunk of your community is saying "hey, we don't want this". And, what, Riot is just gonna go ahead and bully them into playing along anyway? That's frankly a terrible way to do business.
3. If most people don't care about this problem either way, why does Riot care so much? Why would Riot insist on having the whole population autofill with no alternatives? Would it be really hard to autofill as optional instead of mandatory?