I have an older laptop which is set up to dual-boot between XP and Linux. It only has 1GB of memory and the dvd drive crapped out years ago so upgrading is not an option. The Linux version I have on there is long-life, but updates ceased at the end of last year and it was a *lot* younger than XP. Suggesting that a Linux release will be around longer than XP was is being optimistic, and if there is such a beast, was that choice obvious 10 years ago?
In my previous job 10 years ago I had responsibility for maintaining a small Linux server for three years. I was running NFS and FTP on it. In those three years the distribution's FTP-server-of-choice changed twice, I kept with ProFTPD because that way my scripts still worked.
XP was supported for far longer than any version of Linux was.
What upgrade path should they have taken? XP's end-of-life was actually deferred a couple of times - basically because Vista was such a turkey. Once Windows 7 came out that option was no longer necessary. Apple also have shorter cycles than Microsoft.