I know this topic is useless but i'm just testing the waters to see if anyone else shares my opinion.
I had been playing since early vanilla in several top 10 world guilds, aka not your average casual player.
The number one reason i quit wow was because of the constant non stop same bullshit spam into tradechat, which is there because boosts4gold is there which is how the playerbase became so divided, which is why noone plays with any "new" player ( not meaning new to the game, but someone they havn't played with before).
I've probably got a great deal to do with the hype of boosting services, as myself and a team of players were some of the first ones to actually sell services for gold in the game, which started in the Naxx era by selling Undying and Immortal titles - yeah we sold roughly 7000 titles across all of our characters.
Back then litterally noone was boosting4gold.
So yeah TLR:
Quit because of gold-boost-services and it's effect on the playerbase.