Honestly, rather than an LTS, I think k8s needs a much better upgrade process. Right now it is really poorly supported, without even the ability to jump between versions.

If you want to migrate from 1.24 to 1.28, you need to upgrade to 1.25, then 1.26, then 1.27, and only then can you go to 1.28. This alone is a significant impediment to the normal way a project upgrades (lag behind, then jump to latest), and would need to be fixed before any discussion of an actual LTS process.