PC gamers in the mid-to-late 90s apparently started turning up their noses at turn-based strategy games in favour of the new hotness of the Command & Conquers and Warcrafts of the day
A review of X-Com Apocalypse from the time:
"to be honest, the new real-time combat is so good I really can't see why anyone would want to play the much slower (and often infuriating) turn-based tactical game"
:kitty-cri-screm:
spoiler
That's like preferring Diablo over Fallout
Also cheaper to make a game that's just an arena withough having to think about level design or story too much