The government auctioned off this spectrum with full knowledge the problem existed. Each branch of the government stayed inside its own funnel beyond pointing fingers, or the optimal solution of including the cost of updating aircraft would have been rolled into the requirements for winning the spectrum.
Regardless, I truly LOL at the other engineers here that would like to convince anyone that it should be straightforward and reasonable to make updates to ancient certified hardware just because it is ancient and non-efficient. I am sure it plays better on non-aviation websites though.