well.
Let's do a little thought experiment.
Let's say we're at high elo. At high elo there's not a lot of players. So lets say there's only 10 people in the queue that "qualify" for the game, elo-wise.
let's say that supports are under represented 20% (that's close to reality in bronze); relative to mid/top players. meaning, there are 3 mid/top players and only 1 support.
Now, you can't have a game. What happens next?
Either all 10 people wait until the elo criteria of the game gets wide enough such that there's another support that qualifies, or one of the 10 original players switches roles to support.
if the elo criteria of the game gets wide, the support that you're gonna get is going to be either above your pay-grade, or some boosted, useless fool.
end result: you wait 30 minutes for an inferior game.
OR, one of you switches to support, and you get to play without any plat/gold plebs in your game.
TL;DR: you are grossly under-estimating the loss of match quality that follows the variations in "player quality" resulting from a long queue time - a figure that is not visible to you.
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For what it's worth, I'm on your side. You chose to wait 30 minutes for an inferior game; if you wanted to not wait you'd put "fill" in the box and had a game in 5 min top.
So i think, RIOT can maybe respect your choice to pay with a long wait time.
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But I think what's bothering them is a lot of people not understanding that they are making a choice. A lot of people can't understand why they can't pick mid and have a game in 5 minutes. So they scream at riot and riot thinks changing the game is easier than educating fools.