I don't believe this headlong rush towards more and more runways is sustainable and as a UK tax contributor I certainly don't want tax spending on this hub domination madness.
The value of inbound tourism spending taking advantage of the larger number of direct flights available is the key driver, along with the obvious fact that London has a much greater proportion of people flying on business who need the critical mass and frequency of a hub.
Wasn't building runway 3 at LHR a privately financed project?