Didn't WoW lose a lot of it's players because of all the time gating, time sinks and borrowed power that have infinite power creep grinds that you lose each expansion?

There is plenty of content for average players. Mythic+, heroic raids and arenas are all for "average" players.

Yes, they implemented a lot of easy world content for those that prefer that. They also didn't tune things properly like their war fronts and island expeditions. They were pretty unfailable. But there is plenty of content for average players.

It was the endless grind that didn't go anywhere that got most people upset.

And that's something that ffxiv doesn't do.