Who would be stupid enough or dumb enough to use HDDs and/or a server for that long?

Lol as long as you have good backups and are okay with a little downtime, no big deal. That's one advantage with smaller practices. Bigger practices, any downtime is unacceptable due to the high burn rate.
With virtualization and SSD's, I can see most people running stuff for 7 years instead of the usual 5. You just have to go with the latest supported OS as the time of purchase of your server if you want to do that.
Server 2016 = Good til 2026
Server 2019 = Good til 2029