Yes, your way is definitely more scientific then the methods Nielsen uses.
RSNs have lost about 55-60 Million subscribers ( out of 100 Million), if people cared that much about them, then services that carry them, their losses would not be as bad as they are, people would subscribe to those that have them.
DirecTV has a much higher percentage of losses then Dish, yet they carry all the RSNs.
Comcast carries them, yet have lost about 8 million subs, Charter just had their biggest lost ever in a quarter, it carries them.
YTTV, when they dropped the RSNs, were at 2 million subs and the price of $64.99 in 2020, since then, price is $73 a month and have gained 6 Million more subs with no ( except for a few NBCs) RSNs.
The services that report the biggest losses every quarter, are Comcast, Charter and DirecTV, who are the main carriers of the RSN, never a gain, last year they lost 6 Million per sub fees, this year estimated 7 million, by the end of 2025, they will be gone, totally unprofitable.