I don't believe tube drivers' pay can be the market rate. If TfL announced 1,000 new jobs tomorrow at £40k, I'd be amazed if they couldn't fill them with suitably competent and professional people. TfL don't do this because of Union power. It may be comparable to train driver pay but this reflects the power of the unions across the industry.
Of course, we could say that this is good, and that unions should have the power to impose pay levels above the market.... This is a socialist ideology though, and nice as it sounds, socialism just doesn't work.
Of course we don't live in a utopia, and there is poverty, but in the UK, by and large, child nutrition, life expectancy, healthcare and education provision, peace (developed countries don't go to war with each other - people have too much to lose!), and a whole host of things are immeasurably better than they were 100 years ago, and this is all a result of a capitalist economy.... It may not be perfect, but it's the least worst option we have, and for all it's noble idealism, socialism has never delivered what capitalism has.
The tube unions may have some valid points, and I'm not disputing those, or even their right to strike, it's their stranglehold on the industry that I have an issue with, and how it impedes the development of London and Londoners as a whole.