Its a mix of things. PvP isn't popular in this game, its late in the season and they didn't add anything new to the vendors so the crystals you get are worthless. Topple that with de-ranking and a lot less people are bothering to queue. Yes it sucks to get people in crystal that probably shouldn't be crystal, but this game being as hyper casual as it is just means those people are less likely to keep playing when they keep de-ranking. Also certain maps the queue dies down. I've noticed the wind map has the longest queue times.