Yes, however linux supports this sort of security right now and has for many many years, and properly used would have prevented these mishaps. More than backing up their data, I blame the users for being incompetent users of computers in general.
Linus supports selinux right now, the only issue is that applications ship with policy about as often as they create their own user (actually, maybe a bit more often).
I'm saying that people can set up this policy themselves. I'm not saying steam should do it, I'm saying anyone can do it for any application they install.
