Yup, that is the whole point of market economies, they self correct eventually. I totally sympathize with the folks in London it sucks not being able to find an apartment, so you end up either in a horrible commute or working elsewhere. That makes it harder to find people to work there, so if the imbalance persist the jobs move elsewhere, and the revenues go down, and the economy cools off.

So if you're in your 20's today, something to think about is how this might self correct. Either telecommuting could take off, or something like Musk's Hyperloop dropping off people from one urban center into another. Ask yourself what is it about London (other than the job) that makes it a desirable place to live. Can those things be replicated outside of London? Can you build an urban 'night life' center and split the night life from the work life? What is it going to do to the cost of businesses that have to be in London? Can those businesses be made more efficient or profitable by enabling them to minimize their local footprint? On and on. It really isn't sustainable, and as Charlie points out the crash is going to be pretty epic. So think about how you might turn that to your advantage in 10 years.