To be honest Path of Exile offers personal loot and people still don’t play together much, I think the genre is not that great to play coop in front of what other genres can offer like a shooter like Back 4 Blood, Vermintide, Deep Rock Galactic. a CRPG like Divinity OS2 or even racing gams like the latest Forza.
Multiplayer games have evoived, sadly D2R is still D2 at its core and does not offer anything more by playing coop than competing for loot or reaching lvl 99 faster and if we’re talking about pvp it is very unbalanced and there are way better experiences to have in pvp in other games.