the Cowboys used to be the tip of the technological spear, being the first team to use computers for anything, for instance. Everyone knew Dallas was technologically superior at this point in time.
so, as for the philosophical question - has the draft and develop philosophy been supplanted by single season free agent gobbling as the most effective way to reach the top? Recent results say yes.
I doubt this has gone unnoticed by decision makers in big D.
So, now, we must ask why no change in Dallas.
I think it boils down to one of two reasons why: Either (1) you can make more money (not spend as much) staying status quo and being unwilling to risk dead money, or (2) its just plain stubbornness to change/pride to not change.
Many folks think its the stubbornness/pride/ego thing.
I definitely think its the money thing. They are not as simple-minded as some think. A lot of people make a lot of money crunching numbers for the Jones fam. I'd guess pretty darn good financial minds are involved.
At some point, the value of a championship will bubble up to the top of the priority list, as determined by those minds. When it does, we will probably see the change. Until then, we will just hope we get lucky.