(comparatively) more shops are migrating to the newest version more quickly than beforeYou may be right. A lot of companies were holding back on all sorts of IT purchases in recent years. Win7 seems far more acceptable than Vista and people do seem to be priming themselves for wider updates. But looking at the new Corvette is not the same as buying it ;-) and I wouldn't expect the uncritical behavior we used to see in the old days- a lot of these people will wait for SP1 and may well decide not to spend their precious $$$$ when it comes to it.
Also, we need to watch for selection bias. If we base transportation trends on people who go to bike shops, we might conclude that most people are using or considering a bicycle to commute. ;-)
"... They ne'er cared for us
yet: suffer us to famish, and their store-houses
crammed with grain; make edicts for usury, to
support usurers; repeal daily any wholesome act
established against the rich, and provide more
piercing statutes daily, to chain up and restrain
the poor. If the wars eat us not up, they will; and
there's all the love they bear us."
-- Shakespeare: Coriolanus, Act 1, scene 1
