As you mention in your post "As far as the entertainment consumer segment (particularly those who are on desktops) goes, a tablet makes more sense for them than a laptop. " That is a huge segment of the population. So, if that segment goes missing or even partially goes for tablets, the total number of PC's shipped will go down in a big way. Atleast, PC sales can't grow from here. Also, as the tablets become more and more powerful, one should be able to run more memory intensive applications. I have seen a couple of people around me whose overall PC usage has gone down drastically after owning a Galaxy S2 or iPhone. Not is disagreement with your points but I must say that if we are not yet in the Post P.C era, we are fast moving towards one.