The Russians have mounted a ZU-23-2 to a BMP-1 to create an ersatz infantry fire support AFV.
https://www.forbes.com/sites/davidax...h=1757008538c0
Apparently, this isn't a new idea. TIL, the Armenians fielded a bespoke version (see pic).
I think a lot of AFVs that manage to survive until 2000 would not primarily perform the same roles that they did early in the war. For example, this Franken-BMP would be more useful as an infantry support AFV than as a true APC/IFV.
-