An affluent post-scarcity free-time society where nothing matters anymore and everything is a hobby which people largely pursue in groups of the like-minded is by definition beneficial for ALL.

Beneficial for all isn't any part of your definition, you're just asserting that it would be beneficial. Personally, I find the idea of a society where "nothing matters" to be dystopic, and I would not want to live there. Vacation is fine for a couple of weeks, but after that it palls.