This is the current issue. There’s really no incentive for most people to ‘learn’ the game.
They aren’t interested in difficult/hard content. They don’t feel rewarded min-maxxing or competing. Grinding isn’t a thing people enjoy. Many players don’t want to sit down to play Guitar Hero x WoW. It doesn’t do anything for them.
Why would I want to sit down and spend hundreds of hours in WoW learning it, when I could play and beat 5 or 6 other games in that time, enjoying myself more? This is the mindset people have when looking at this game. The ‘one’ thing it had in the past that helped it stand out. The socialization that happened. The ‘world’ you were in, has largely been ruined in many ways over the years.