Being wholly private means short termism wins over legacy and planning. Sure EDI and GLA are growing strongly and making money for their shareholders, but over the next 50+ years would a proper greenfield site plugged into national rail be better for the country?
EDI is well beyond design capacity and is now at the 1970s Heathrow stage of just bolting add ons left right and centre after closing two “spare” runways and kicking out all GA. That does have an ROI and kicks the full rebuild can 15 years down the road but that airfield needs a whole new terminal sooner rather than later.
Of course the Govt would have to buy out and close both GLA/EDI and that’s not affordable sadly. Strangely enough, suddenly, there’s something to be said for a BAA type of operation. Competiton is driving traffic in Scotland but at the price of two less than stellar airports.