Hmm, maybe achievements aren't as popular as I once believed, but I do think there's unnecessary friction to joining a friend's game with Epic's half baked model. It's one of those things that nobody notices until it's missing.
I'm not saying you need a full social network on every platform, either.
Nobody cares about centralised achievements any more, and most people don’t particularly like having different friends lists for each service.
People would rather organise a game through something like Discord that is entirely seperate to the store ecosystem.