The playerbase is increasing.
Open games take long to fill, especially after the introduction of Quickmatch. If you want a game fast, try joining that.
Everyone has different objectives in the game. Some people want a high level, some want a good roleplaying experience, some want to compete on the ladders and be the best.
The strategic community is usually willing to teach you a thing or two. I suggest joining the Warzone discord and ask some more experienced players for games! https://discord.gg/vaWfhrW