I recently migrated some home services (email, contacts, calendar, DNS, DHCP, VPN) away from MacOS knowing this was coming. My Mac Mini is pretty much limited to Indigo and a web server that hosts the plugin. I can't see Apple releasing an updated Mac Mini (even though Tim Cook said it was important). Would one buy it simply as a controller for device management? I would think an Apple TV could do the same job (I don't have one) - perhaps it will in the future.
I have a NAS (circa 2010) for file sharing and Time Machine backups. I highly recommend over running on MacOS. Costs have come down significantly over the past couple of years.