But the matchmaking cant get 12 people to make a match?

There are a few reasons you might be experiencing slow matchmaking. If you are very highly skilled, it will take the matchmaker a longer time to find you a match because it is looking for other highly skilled players to match you with. If you're playing in off-peak hours in a smaller region it can cause slow downs. If you're playing a less popular game mode, it can take longer.

Without more information about your particular situation, it's difficult for us to deduce why you're having a hard time finding a match.

I'm looking at the average queue times across all regions and all platforms right now and every one of them is below 60 seconds. The longest queue times I am seeing are on console in Competitive Play, but even those are averaging less than 60 seconds.

Information in Jeff Kaplan's post is now outdated since the introduction of Role Queue for Quick Play and Competitive Play.