Why cant 3v3 have a solo que system? I understand that less people play 3s but cmon

I like how you answer your own question right in the title.

But it's more than just low population, it's the fact that solo queue does not accurately place people based on skill. Do you know why solo queue works in SR? Here's a hint: it doesn't (almost all top players are duo queue spammers).

I solo queue on 3v3 all the time. restart your computer and see if that fixes it.

less players, less people needed for a team if you are only concerned about better opponents, you can still climb in hidden mmr in normal games.