And that wasn't even the problem. The problem of the "budget" is that the studio stuffed the costs of several initialized, then aborted attempts at the series ST Phase II, and multiple switching back and forth between movie and series onto the budget of ST:TMP.
If you look purely at the budget for TMP, and then deminish that by the simple extra costs of the studio jerking about, TMP was more than cost effective.
Which is a bit like saying that if you only look at production costs for Item A, the returns on Item A are better. Well, that's true, but you can't just look at production costs for Item A, you also have to factor in the costs of research and development of Item A (whatever Item A may be). It is part of the job of Item A to pay for the costs of its development -- just like it was part of the job of Star Trek: The Motion Picture to pay for the costs of its development (and yes, that includes the costs of developing Phase II).
Bullshit.
Star Trek Phase II is not research for TMP, it's an entirely different production. It's like having been making a series called "Knight of New York", and then deciding by studio-politics to pull the plug on it. Then you, the studio, make a movie that you hand over the same production crew/company called "Grand Star" and putting the costs of "Knight of New York" onto "Grand Star" because you happen to hand both projects onto the same production crew, and if the movie can't clear both budgets blaming the production crew for it.
EVEN IF you do add the costs of ST Phase II onto TMP, then the blaim for the "bad performance versus costs" needs to lie squarely on the people responsible for jerking the production company around with internal politics causing the problem:
Namely YOU, the STUDIO, NOT Roddenberry, Wise, and company.
And it's fair enough to argue whether or not TMP should have been saddled with the job of recouping the costs of Phase II development. But, remember, it was, ultimately, Paramount Pictures's project; they have the right to whatever financial goals for the film they want and to judge it by that standard. They determined that whether it was Phase II or TMP, it was all Star Trek, and that therefore the final product, whatever it ended up being, would need to recoup the costs of developing any earlier unfulfilled Star Trek project.
You may think it unfair, but they didn't, and they're the ones who owned Star Trek and made the decisions. It's not like this is a matter of objective fact.