What you’re suggesting is for the game to focus exclusively on entry-level content. Because that’s the only reason what you’re describing works in some other MMOs. They focus on easy content where your skill and gear doesn’t really matter. If hard content exists, it’s either negligible (ie: not much of it, or not rewarding enough to matter) or something like WoW’s Mythic where the vast vast vast majority of people won’t bother.
WoW still has that entry level stuff where you can bring unskilled, ungeared friends and have no issues. But many people prefer to actually push content appropriate for their gear, so of course they’re pickier about who they’re playing with.
That’s not a bad thing, it just means WoW has varying levels of content and not every level is appropriate for every player.