IBM still maintains the platform: I’m sure there’s still system updates and the like, IBM just has done a better job maintaining backwards compatibility than “m

IBM still maintains the platform: I’m sure there’s still system updates and the like, IBM just has done a better job maintaining backwards compatibility than “modern” stacks: e.g. the AS/400 has gone through a couple different CPU architectures without requiring that programs be recompiled because it was designed to decouple the code output by a compiler from the machine code of the underlying platform.