If you look at the issue being actor fatigue instead of cash, the episode looks a lot more like a bottle episode.
The main character for the episode is someone who would be considered to be supporting cast. The only other characters from the show with significant screen time are also supporting cast.
It is an expensive bottle episode, but the scenes take place in a modern day city with a deep film industry. That is one step above TOS having an episode in a Western setting because the soundstage for it was already built.