A lot of mistakes being made with high dollar QB contracts. One thing for sure though is you better have the team around them or it will not pay off. Carr is a prime example of that. They are wasting a lot of money and by the time his deal is done, they will have nothing to show for it. The same thing will happen with the Cowboys with Dak. It will not be because of the team around him though, it will be because of HIS limitations!
There are only a handful of QB's that really can make it work with that much money given to the QB (the 25-30 mill) because THEY have the ability to overcome those other deficiencies! Dak is not that guy, Cousins isn't, Alex Smith isn't, Garoppolo probably is not, Stafford is not. Giving your QB that much money is just to keep the fans in the seat to have a watchable product, but it is not going to get you a title!