If someone needs an irrelevant number to keep them playing then the game is done. Solo players won’t be doing the activities that require 350+ which is the level everyone should be at by now. Players with active clans and who use LFG will be able to do end game stuff to get to the level they need above 350+. The rest can chase crucible glory and valour quests, vendor ranks, ornaments, exotics, armour sets, eververse gear, whatever. The power level isn’t the be all and end all. Never has been.