The idea itself has merit, but yes the entire community has complained about the 40k cost ever since it was introduced. There has been NO communication about it though, and it was added back with Hades in April.
I am convinced that testing is not performed with any realistic gameplay expectations, because yeah there's nothing that winning a single mission could offer that would *ever* be worth 40k. And it's not like it even guarantees a win, you can still lose.