Just like some airplanes that been in service for 50 yrs and scheduled to remain in service at least another Fifty.
Them KC-135's are getting pretty damn old. I believe we've got a replacement lined up for them though.
I think they canx'd the plan to replace the B-52's.
Edit: Yep, being rebuilt over the next few years, expected to remain in service into the 2040's.
In most sports, cold-cocking an opposing player repeatedly in the face with a series of gigantic Slovakian uppercuts would get you a multi-game suspension without pay.
In hockey, it means you have to sit in the penalty box for five minutes.