"Alessandro finished the story and reached the level cap of 60, engaging with some pockets of endgame content across 25 hours with Diablo Immortal. He didn't spend any money..."
Sounds like a pretty good deal to me.
You've engaged with all the content for free, all that remains is the endless grind of stats and equipment optimization.
There's nothing else to experience. The remaining gameplay loop is endless. You are invited to pay to climb faster, and you absolutely don't have to.
I think people are overreacting, when it comes to monetization for this game.
lucidique's comments