Is that really the goal though? You can have a successful MMO without killing wow. Warhammer Online, Guild Wars 2, etc. were all great games from the business perspective.
OP said:
>all these mmos were popping up saying they were the "WoW killer"
Guild Wars and WHO weren't positioned as WoW killers. They were positioned as WoW alternatives that prioritized or PvP or had an endgame that revolved around PvP. Which is probably why they did well - they offered something that WoW wasn't good at instead of trying to eat WoW's lunch.
Edit: Rift is probably another good example, though less high-profile than SWTOR.
What's funny is WoW has declined so much but is still clearly a viable business, but I'm sure things like LOTRO, City of Heroes and Tera peaked at higher levels than current WoW. But the WoW of their time was on like 10-12million subs so that was a failure.