Overwatch "ranked" mode sheds light on why Riot made Dynamic Queue.

For those of you who don't know, Overwatch had a ranked mode in closed beta. It was removed to be "tweaked" and re-released after launch due to complaints from the competitive players. The problem was essentially that all you had to do was grind enough games and you could get to the highest divisions of play. Even a 40% winrate and you would eventually wind up in their version of Master.

Now, why did Blizzard implement this kind of system? They outright tell you in some dev interviews. The short version is that they realized that almost all players liked going up in rank, but that the part they didn't like was struggling to go up and failing. Players want higher ranks, but what does Blizzard want? Blizzard wants people to keep playing their game, they want player retention and enough people playing at all times to keep queue times short. Solution? Turn ranked into a grind. That way players have to play a ton of games (what Blizzard wants) and they always go up in rank (what players want).

This isn't exactly the same thing as Dynamic Queue, no. But it's a similar thought process. Players want to go up in rank? Well, what do we want them to do? What do we get in return for giving players higher ranks? For LoL, the answer to that question was NOT "play more". LoL players already grind like mad, Riot doesn't need to incentivize that behavior. But what they DID want to incentivize was social play. Social players quit the game less often, and social players spend more money, those are Riot's priorities. So in exactly the same way Blizzard undermined the skill-based nature of their ranked play to incentivize grinding, Riot undermined the skill-based nature of their ranked play to incentivize playing with groups of friends.

And both companies thought they could do this for the exact same reason: they think you're stupid. They think you want higher ranks because "DURR, SHINY BADGES, ME GOOD AT GAME", not because it actually reflects your skill. Not because it means anything.

And every day you keep playing, every time you spend money, you prove them right.