Key Blizzard developers apparently tried for years to get a new Starcraft or Warcraft RTS off the ground, but execs had 'no appetite' for them
Throw that in with a lack of features present in the 20-year old original, a crappy EULA that gave Blizzard ownership over what you made in it, and the fact this thing released during the nightmare of the studio's rep-tanking controversies, and you have the final nail, one which fan reception drove hard into the genre's coffin at Blizzard.