Vettel won't leave Red Bull for the foreseeable future. They are producing fast cars. Why leave?
On the face of it I agree with you completely. He is fast, and the car is fast. The team love him, he loves the team, and there does not appear to be any politics going on, which is a great testament to Christian Horner.
But allow me to play Devil's Advocate - what about their reliability situation?
Imagine if you were getting loads of pole positions, say 2 out of 3 races (so the speed was definitely there) but finish just a handful of those races because the car repeatedly had failures, say 2 out of 3 races.
All the while your rivals continually scored solid points/podiums/victories because they actually got to the chequered flag, and you were (relatively) low down in the championship table. What would you do?
An extreme situation I admit, but could that be the story of Red Bull's 2010 season?