I actually think it's the opposite; the Corvette has elevated its performance to the Vipers level, not that the Viper has been tamed.
Ralph may have said that he was trying to make it more livable, but it's still very much a drivers car that will bite you. Even Randy Probst said in his Motor Trend review that the car scared him when trying to push it. Others tell me he's not really a good driver and there's no way a stock ZR1 would beat a Viper (this was from people who have track driven both and don't work for Chrysler).
I think part of the problem with Viper is it used to be a single halo car, available in coupe and roadster. Now there are 4 Viper models (SRT, GT, GTS, TA) which probably doesn't support the low volume of each, and there's not even an ACR yet. Also, SRT tries to keep their cars easy to maintain for track days for the grassroots enthusiast. Because of this the new car didn't get things like carbon ceramic brakes, which I feel should be on a car of that price. That would elevate the performance and make it more exclusive, however, a large percentage of Vipers do see track time and I'm sure this is a probable reason for their decision.
Sergio mandated that every brand had to stand on its own and be profitable. Now that SRT is gone and absorbed by Dodge, they can afford slimmer margins on these cars and still keep the books balanced.