Then I think there are several things you can do to send Riot a message. A way to show how we don't approve of their decisions.
-Don't buy Prestige Skins/Event Passes
-Don't play TFT
-Don't Buy Eternals (when they come out)
If Riot see's that less people are buying event passes/prestige skins, they might stop releasing prestige skins so much and/or might put actual effort into them. If they see people playing TT they might consider keeping the map, or, if we're lucky, actually try to balance it. If they see less people playing TFT they won't divert as much attention from balancing other game modes. The thing is as long as their decisions work to increase profit, they will go through with them. Regardless of public opinion. If these things don't work, they'll try new things, and maybe, just maybe, they'll start taking risks.