Is Wiggins really 'competitive year round'? It's difficult to say, because he's only just really found his feet as a GT rider. 2009 he didn't ride as a leader until about 2 weeks into the Tour.
In 2010 he tried the Menchov/Schlecklet approach of riding a fair few races without really trying to be competitive, and it didn't work for him, so he changed (fair enough).
In 2011 he did decently in Paris-Nice, but on a parcours hugely biased to the time triallist. But he then didn't do much of any note until the Tour build-up (with the Dauphiné win obviously the key point here). I'm not convinced he'd have been doing the Vuelta had he not crashed out of the Tour - certainly not at the level he did it.
In 2012 he's had prime early form again, perhaps better this year too, so it remains to be seen how the rest of the preparation goes. He looked to have hit the Tour in good form last year, but as we know from Evans at the Giro in 2010, sometimes it's hard to be at the top in June and sustain it for a whole GT. Wiggins tried the Schlecklet approach and clearly it didn't work for him, so he's trying a different approach, which appears at least on the face of it to work better. After all, now, even if he screws up the Tour, he's likely to have a good season.