TheCleanerDragon
Squad Leader
With traditional RTS, that's partly because the genre has fallen in popularity since its heyday in the late 90s/early 20s, so the market just isn't there, or isn't perceived by publishers to be there, unless you have the name-recognition and nostalgia-appeal offered by one of these franchises. If a producer was going to sink big bucks into a wholly new franchise, they'd expect something more in the vein of Total War than Total Annihilation.
I don't think that a similar dynamic can describe the Disney remakes, because animated children's films are probably at their all-time commercial peak.
What I said earlier was a bit too wide of a statement, there are plenty of new or RTS games, just not traditional ones like Command and Conquer. I forgot to mention, Microsoft is making Age of Empires 4 so they are doing something new even if it's part of an established franchise. I have to agree that the dynamic definitely isn't the same, Disney has a massive consumer base to sell their movies to so there's no need to innovate. on the other hand there aren't that many people who play traditional RTS games, so unless they spend a ton of money on marketing it's not going to sell all that well.