Well he's said many times his focus wasn't on the road until late in his career. And lets be fair, his tour win was basically the planets aligning. Poor competition, TT-heavy parcours and the strongest team by a country mile. Coupled with it being a Olympic year, in London no less, where peaking for the Tour meant also peaking for the Olympics.
I'm not surprised he doesn't want to race another GT, the chances of him winning are very small and for guys like Wiggins it's all about winning.
Wiggins is a brilliant cyclist, I'll not take that away from him, and I hope we see him shine on the track again, but road racing is different. He doesn't want to be another one race a year only about the GT figure, he loves cycling too much for that. The track will allow him to back off on the weight loss, spend a bit more time at home and get back some confidence he's probably lost early this year.
He'd be relegated to a Tony Martin-esque role in the peloton. Able to compete in one week stage races and used as an engine at GTs. Not what he wants.
I wouldn't be surprised to see him have a stab at Paris-Roubaix over the next couple of years.