I don't dispute that but why should it pay for TFL's upgrade when TFL earns so much from tube ticket sales?
Should HAL be paying towards BA's fleet upgrades? After all BA flies into LHR and bring passengers to the terminals to shop.
TFL runs the tube network to multiple destinations and makes good money from it. Why do you expect them to start asking popular destinations to contribute towards running their business? Should the museums also contribute? What about Harrods, Buckingham Palace, Tower Bridge etc. They all rely on the tube to bring them customers. Should they be giving TFL money?