''Are we to believe airport charges here are so low they can't afford the required investment?''
Sober Lark
Though i can't speak for heathrow i do know that the above is often exactly the case. In many smaller airports profit per passenger is tiny as the low cost airlines these airports rely on have the commercial clout to force very tight deals.Charges such as car parking and profits from shops are all that's left to make a small profit.