Is Riot trying to tell ppl to give up having MID as their main role?
No, just a lot of ppl want to mid compared to other roles.
It's not exactly rocket science...
It's not like Riot is purposely making mid players wait longer and forcing people to support. It's basic supply and demand: more people want to mid and support, so one has more supply and one has more demand. The people in abundance have to wait longer to finally get to play their role, and the role in short supply gets people autofilled into it more often.
If roles were more evenly distributed in the first place, before the slippery slope could take effect, we wouldn't have this issue in the first place.
Instead of going top/mid (aka the stereotypical solo carry roles, no offense but that's why they're popular), consider learning one of the other three roles to do your part in alleviating some of the unequal distribution of roles that's causing the queue bog in the first place.