What are you basing $20-25 million on? We have no idea what Spectrum, Xfinity DirecTV, FOX9+ et al are forking over to the Twins. It could be practically peanuts, based on the lack of leverage they have.
Regarding the advertising revenue, while they do have some solid sponsors, a good chunk of the commercials are the Twins themselves & their charity foundations.
I also don't think it's as low as $3-4 million in total. But I also don't think it's as high as $20-25 million either (which as you indicated is already a mighty fine haircut to begin with).
The start up overhead is also a huge mystery. Totally in the clear, I could see $15 million as reasonable. I would be less surprised if it's substantially less as opposed to more.