Silver streak
Whilst it would be possible to centralise mail/cargo operations to PIK, it should be remembered that mail is time critical and the extra time for road transport is a critical factor.
PIK location on the West coast and it's excellent weather and low fog risk was i understand the main factor in its location in the days before precision approaches were commonplace.
I have flown for a number of airlines that use PIK as a designated alternate for GLA/EDI but if and when we diverted we never went there, it was purely for planning purposes because it was always above alt minima, but no revenue for PIK in that!!
It maybe possible to down scale the airport to reduce costs.
Skippy
They may have bought it for £1 but you and I know the real cost is the liabilities, i have no idea what they are, but it will likely be millions and probably 10"s of them.