I see what you mean. And my goal isn't top split hairs, especially to death.
In software, mission creep has a fairly well-understood sense. It involves getting sidetracked, pulled away from making progress towards your main goal through some combination of factors, including but not necessarily limited to paying too much attention to what should be secondary concerns. An essential element of it, though, is that it occurs unintentionally, accidentally, so slowly you don't even realize it's happened, until you've already fallen victim to it. Hence, the "creep."
I do not believe that Axanar failed because they lost sight of the main objective of making a film due to their focusing too much on the studio and the merchandising instead, and getting lost in that. Rather, their decision to set up the studio and sell merchandise signaled that they had by that point elected to pursue other objectives and put off direct work on the fan film, at least temporarily* but for the foreseeable future. That's a red flag. Not mission creep, but flat-out either change of mission, or (again with the positive spin) clarification of their mission after realizing just how far they had to go.
To get us to utopia they had to build the bestest train to get us there. Sorry, my snark may just be starting to show, now.
* - "Everything is temporary!" — Cosmo Castorini (Moonstruck).
