If you continue to dumb down the game, you will lose half your player base

[Y2K21]

Blizzard stopped reporting subscriptions during WotLK, and the player base began to decline as the expansion grew older. Everything came to a head, and exploded in Blizzards face with the release of Cataclysm.

Blizz stopped reporting subs during WoD when the game lost 50% of its playerbase due to bad game management decisions.