For the vast majority, affordability does affect their choice. While not cheap, a vette is in a whole different ballpark to the nsx (50 to 100 vs 200+). I'm still not convinced that the NSX would win me over even at even money, but at two to four times the money, my decision is very easy.
I'll say that most car guys are secret rednecks with toys. Listen to a lumpy 6.7L v8 cold start vs a turbo-whatever, and unless the turbo-whatever is hailing from an Italian marque or Aston Martin, the v8 just has "presence". Then throw reliability and ease of DIY/finding a shop to wrench on it and you can see why the Corvette is so damn popular.
To be fair, I want a c7 grand sport, big time.