I suspect we're unable to do anything until we understand the brain better, what defines addiction (at a very measurable, concrete way), etc.

The one thing that does scare me about addiction + money is that, like Diablo, the companies incentive seems aligned with getting players to spend vast quantities of hours and money. Regardless of what it is right now or what value it offers for free, that seems to be their incentive.

Simple buy models without MTX seem an easier model to keep company incentives aligned with player incentives.