Hopefully this is a trend they build on. HS still doesn't include any of the security updates, only the "supplemental" ones. I've got several "unsupported" macs still on 10.13.6 and keeping them on the latest security update is an all day event because they don't take OTA updates properly. If they would put the latest build in the installer no matter what this wouldn't be a problem.
Since apple thought it was okay to kill off the MP5,1 I'll have to do the same thing post 10.15 if they keep up this trend.
Perhaps it's time to retire obsolete Macs...