Solo Queue: Why not both?

Personally I'm staying out of the debate on solo vs dynamic queue. I don't have much of a preference. What I don't get is why we don't just have both and have a separate ladder for each.

This game is the most played game in the world, I really don't think it would be difficult. And the solo queue supporters wouldn't really mind a slightly longer queue time.

Rocket League, for example, has many different queues. They have a much smaller player base but still pull of 4 different ranked queues as well as 5(I think) normal a queues.

Perhaps there is a good reason not do just have both, like riot said they had initially planned. If there is, please tell me! But truly I don't understand why we can't have both.

As a side note, I've heard the cynical fan-created theory that if we had both dynamic queue would become super unpopular. Two things, 1) I feel like it wouldn't really go out of favor and 2) Does it matter? How about we let the game take its course. The boards aren't a good representation of the community, so let's just test it out to see which queue ranked players tend to like better.