Both games are similar in their cycle, but one of them doesn't really care if you keep subbing during drought, meanwhile the other one throws a 6-month promo with a pretty mount so you don't stray far. Due the difference on revenue ambitions, Blizz upkeep is far harder to maintain than SE's.
There no tangible way to say that wow is on a steep declining... except for 9.1.5 which is Desperation: The Patch.
Am I crazy or you are just equating twitch numbers with game quality?