You can harldy call them ancient-it’s production continued into the 90s,making the airframes younger than most US bombers.The strategycenter article says that the newest versions were produced in 2006-with new engines,electronics & weaponry.
For bombers its not the airframe, its the power plants and electronics packages.
Clinton sold the Chinese everything they need to produce what they want.
We have the B-52 which was designed for a shelf life of 100 years. We also have the B-1, B-2, and F-117. Now, we also have the F-22.
If China is able to detect the F-22, then I’ll be damned.