Define *easily*. No one but a hardware geek can use Linux cause it only ever kind-of works - you have to know how to debug and hack it to make it work properly. Equally the ui isn't up to windows standards, well it might be if you are a linux geek and know how to do all the mirad of things to make it work nicely but no *normal* person is going to do that.
My mother is 75 and a happy ubuntu user for several years now. Ill be sure to tell her she is not normal and a geek. Installing can be hard with ubuntu if something doesnt work out of the box. OEM preinstall takes care of that. And installing stuff that isnt in the repository is sometimes (too) hard, but hey, still easier than installing something on an ipad thats not in the appstore .