What did Robber Barrons like Carnegie and Rockefeller do after they had amassed great fortunes and extraordinary success in their chosen fields? They started Endowments and Foundations, and this became as much the "business" as being titans of industry. Unless you figuratively wallow in the muck of new money avarice like a Kraft or Jerrah, at some some point you have achieved enough wealth or winning in this case.
When Rooney got the 5th Ring, he shifted to a legacy and endowment focus. Oh, it had been there in some form all along in social consciousness, but hiring a young, unproven Mike Tomlin came out of the zeitgeist of the Rooney Rule that culminated in Rooney publicly endorsing Barack Obama and accepting the political favor of an Ambassadorship to Ireland. At that point, it was about way more than football. So, it was hardly surprising that Rooney allowed the NFL to gut defensive football -- his brand identity -- and come down with the hammer on his HOF OLB and QB. Rooney's "brand identity" was no longer winning Lombardi's: It became legacy and the endowment of the social capital invested in Mike Tomlin. That's why the Rooneys will never fire Tomlin and he'll at minimum be allowed to let his contract run out and declare victory about all the great things he did in having 4 playoff winning seasons in 15 years.
Remember, the Rooneys were "blown away" by Tomlin the HC candidate. Honest question, has Tomlin "blown away" any of you with anything you've seen from him in 12+ years?
Rooney saw what he wanted to see, and the vehicle by which he would endow his legacy capital.