Realistically what'll happen is these users will start hunting for alternatives. If Linux gains enough enthusiast marketshare, more small local IT companies will feel comfortable just handing folks an old PC loaded with Linux, more computer shops will directly support Linux and this will chip away at the norm. Eventually if such a trend continues for long enough folks will start asking for it "yeah my last computer had oombootoo on it instead of Microsoft. Do they still make that? Can you get me one of them oombootoo computers?"