Heathrow is a dump. It is not, and never will be a modern airport.
It is in the wrong place, is badly designed, and is useless in a modern world.
It is a 3rd world airport.
Anyone who thinks lhr is any good should go to Dubai and Hong Kong to see a modern airport.
So, it needs to go. Build Boris Island, or some other place out to the east, and convert lhr in to a business park and a housing estate.
If it is just money that is the issue, nothing that a little bit of Quantitative easing cannot fix.