>>What people forget is that it costs money to keep providing updates for an old OS, and that improvements in later OSes make them safer to use in the first place.

True. And software doesn't "wear out" like a hard drive or flat-bed truck, so if it makes business sense to keep using it- people can. Just as your husband did. What happens though is that hardware and consumables need replacement and one day there's no driver available for the old OS, just as the manufacturer no longer offers K2C buffer seals for a '57 Chevvy. Maybe if new software drivers had a price tag, it would be different but people expect drivers for free and therefore need to expect to update their OS to get new drivers. It's true of Linux as well- older versions of Centos struggle with large WD disks and newer motherboards, because it's not viable to update obsolete stuff forever for free.