The Air Force already periodically deploys B-2's to forward bases within range of Chinese missile strikes.
https://www.pacom.mil/Media/News/News-Article-View/Article/2...
Current plans are to purchase a relatively large number of B-21's. Some losses are expected and accepted.
The B-52, etc.. is just different. It's not as high value of an asset as the B-2 or the B-21 will be and gets treated differently.