While I definitely agree that it’s always better to follow the wine in the glass if possible, that isn’t always an option. And if it’s a wine or type of wine that you have experience with and know it shows better after an hour in the decanter, why not decant (this is leaving aside the occasional necessity of decanting for sediment)?
Also, I’ve seen too much old Bordeaux wake up after an hour of air to think that decanting is a direct relationship with aging.
But I definitely agree that decanting blindly would rarely be a good idea.
I disagree with the notion that a wine isn’t ready if it needs decanting. A lot of great mature wines – Bordeaux, Burgundy, Barolo, Northern Rhones – benefit tremendously from some extended decanting, and you’re cheating yourself of the full experience in most cases if you don’t decant them, I’m convinced. That can be true with mature white Burgundy, too. (I remember a great bottle at your place once, Jay, though I don’t remember what it was.)
To be sure, there is a burst of flavor in most wines when they’re first opened – presumably an initial bloom of volatiles – that can be magnificent. But often a wine shuts down for a while after that. With wines I know, like those I listed above, I’m comfortable being patient waiting for them to come around with a bit of air.