Seriously people where do you get some of this stuff?!
I gave a complete breakdown of sources for my claims (and many other claims) in a previous discussion about NFL Network and the Thursday Night Package.
The NFL Network is a cash cow for the league with or without games. The network doesn't need the games to be profitable.
Profitable? Maybe, although I've not seen any sources establish that. Cash cow? That's something quite different and I seriously doubt their subscriber numbers and ratings would be anything like what they are today with the TNF games. If you look at the facts we do have, which are the published ratings, the actual live games are the only things that get noteworthy ratings. Would ratings for the other shows on NFLN get better ratings without the TNF package? Unlikely, since the subscriber base would almost certainly be much, much smaller.
You raise the question of giving up a Thanksgiving game. I can't speak to the NFL's reason for that, but I wouldn't be surprised if they could get more money from the networks since it's a high profile game every year. In that sense, it's not really comparable to any of the other Thursday Night games, but more to a playoff game or one-off SNF/MNF game.