Backers are still being asked to pay for it's development
And that is yet another point. Go ask about SQ42 on reddit or Spectrum and a majority will say they don't care about it. They only care about SC itself.
But criticise the development speed and watch how many say "Its because their efforts are focused on SQ42!" as a defense. (Which in itself is funny, because if they are focused on SQ42, then where the hell is it?)
So, many backers are giving money for CIG to develop a game they don't care about.
Now, present that argument and watch the response be that both games share a lot of common tech and assets.... which then undermines the response of why SC's dev is going so slowly, if both share a lot of common effort.
You can play some nice games of mental gymnastics with some backers