That seems like a bit of an overstatement to me. I've been playing for free for a while now. I'm at adventure rank 25, and my characters are all at levels 40-50. I've unlocked all the maps that are accessible at this level. There's a long list of quests and challenges that I have yet to get to. There's plenty of fun to be had without spending money, and in fact I'd recommend it as a good free open world RPG.