Pretty simple to change desktop without dataloss or re-install. Harder to switch distro, (say Linux Mint with Mate) without fresh install, but switching to a later Linux distro than Ubuntu 12.04 is painless compared to XP to Vista, Win7 (bug fixed Vista), mad Win8.x or especially Train-wreck Win10
Dos User from 1981 to Dos 6.22
CP/M 80 from 1980 to 1992
Unix family from 1984
Linux seriously since 1999
Windows 3.0, 3.x, 95, 98
NT from 3.5 to XP (server 2003) and supporting evil Vista, Win8 Win 10 (mostly replacing last 3)
Supporting some Win7 still.
Upgrade of a server recently from Linux Mint 17 to Mint 18.3 was painless. Without any data loss or re-install. Try that on NT4.0 to Server 2003 or Server 2003 to later?
So really only windows left is 7, no comparison between XP hold outs and older Linux version users.