alt Hacker NewsTransport for London (TfL) have a fledgling property development arm called Places for London which aims to try and replicate some of the successes of Japanese railway companies. They propose the mooted Bakerloo line extension is partially subsidised by over-station developments.
TfL can barely build some flats in Zone 2 without the locals rioting like they're destroying a Cotswolds village. Actually, it can barely fix the literal busiest station in the country without a bunch of minor celebrity detractors riling up everyone about how much of a travesty it is that we're doing it.
Without the public or central government support, the efforts you're talking about amount to very little.