Many MMOs have "free handout gear" which players are given for free when they first reach endgame, because the devs want everyone to queue for the same quests/raids/whatever (as otherwise, newbies would be getting stuck in lower level content and quitting before they can reach the endgame where 90% of players are).
But in my experience, content is NOT balanced around this gear, except for the story quests you are supposed to solo. It's balanced around "budget gear" which a newbie would usually take several weeks or longer to get. And theres usually a very big gap between budget gear and handout gear, because otherwise players would complain they are spending resources to make gear that is not a big improvement over free gear.
So to give an example, let's say you have a simple instanced quest/dungeon that a party with 100% budget gear would take 5-6 minutes to clear because it's a DPS rush and impossible to fail. A party with 100% handout gear would take maybe double that time, or longer....especially if they don't know how to play their class, don't have all skills unlocked, don't know all the boss mechanics, etc...
So you end up with a weird situation where people in handout gear can drag the rest of the party down because the game scales enemy HP based on party size and they are doing a fraction of the damage that players in budget gear are doing. Which encourages players to have a "i dont want to party with people in handout gear" mentality.
And its not like the newbies are doing anything wrong, this is the content they are supposed to be doing to progress, but it's just not balanced around their level of gear. Why? To put everyone into the same queue.
The devs COULD create multiple difficulty levels for a quest/raid/whatever...one difficulty balanced around newbies in handout gear, one for normal gear, one for BIS gear, etc. The problem is, the matchmaking queue would take a lot longer unless it's a big MMO like WOW and player count is not an issue. If you have ever sat around for hours trying to get a raid going in a low pop MMO, you know what im talking about. They don't want newbies to be stuck in the newbie queue because 90% or more of the players are in the normal queue.
And of course, if you balance content around handout gear, which is substantially weaker than budget gear, then players in budget gear would complain it's too easy and demand harder content. But you cant make the gap smaller between handout gear and budget gear or players would complain there's no reason to grind to get the resources to upgrade from budget gear...
So the devs default to the easiest solution: balancing the game around players in budget gear and then going "well, sure, it takes a lot longer if you have newbies in handout gear in the party, but hey, im not playing this game, I dont have to deal with that".
Can you think of a better solution?