Irrelevant to watching movies and listening to music chatting with mates and generally using a computer for the purpose of entertainment maybe? Because the real work needs a real computer. One with a keyboard you can type on, a screen which can show some decent amount of information, printers and mice and compilers and more than 2GB of ram. There are more computers than ever in play, their numbers have been eclipsed by all these toy devices however. That does not mean the real computers are irrelevant at all.
And even for entertainment, are you seriously telling me these little ARM devices with no good input devices, ps-1 calibre graphical capabilities, and MINISCULE screens are making computers which run the latest big games irrelevant? People who are into games have been talking about GTA-V and the like lately, not simple side scrollers and 2d physics games where you launch birds at pigs.