I'm not sure I follow you on this. Bally's gets a monthly amount per subscriber from every cable/satellite subscriber in the Twins territory that carries them (DirecTV/Comcast etc.) The last # I saw was there still 1.2 million homes with Bally Sports North, though I'm sure it's lower by now. They get anywhere from $5-10/month I've heard (DirecTV adds like $7 to my bill so I assume they get at least that much). That is the biggest chunk of their revenue (and the Twins make up about 40% of that value with the rest the Wolves/Wild/Other). The ad revenue from Twins games is a much smaller slice.
Also, while Dick Bremer and Morneau etc. were/are paid by the Twins, I believe BSN was bearing the cost of equipment, camera crews, producers etc. I'm not 100% sure on that though.