Obviously GM disagrees, and they have done extreme polling of current Vette owners to come up with their conclusions.
Having said that, I've been in a couple of E46 M3s, and I don't feel the interior is as nice as the Vette's. Of course, much like what you said, that is an opinion. And in case you weren't aware, the interior of the Vette is totally unique to the Vette. It doesn't share parts with anything else.
In terms of cost, GM is where they want to be to sell every Corvette they produce. Obviously the buyers agree, as the Vette plant always works at maximum production.
