> I guess I misjudged Apple's commitment to support HFS+ long-term.

One thing I have learned with (current) Apple is to never trust their commitment to support something they're not using. And even be wary for stuff they are using. (in my mind, a core technical difference between Microsoft & Apple is that MS will bend over backwards for backwards compatibility, whereas Apple will drop it as soon as they can, and sometimes sooner still)

They replaced their use of HFS+ with APFS in 2017, so it's had a good run.