No one likes getting farmed. No one wants to go through some kind of hazing ritual to get gear. Add in the items and boosts that create another level of garbage to dig through for a new player and the power disparity becomes even worse.
“Nevah been easier to gear…” fanbois are delusional about the power curve differences between players. If it’s easy, than make it not matter. If skill is the great equalizer, than make more skilled players have to fight with a handicap if they want to get honor points and awards in casual bg’s.
Even rated and competitive play has some gatekeeping for how players are paired up. In casual, it’s just a mess, and it’s no wonder that it’s hard to keep players. You could give players an indefinite ban for leaving, and all it would do is make them not play at all.
Epic BG’s have no rating requirements, and you have very little if any choice on who you team up with. Premades are just the final nail in the coffin. It’s not like Blizzard has done anything visible to make matchmaking better.