The "supply and demand will equilibriate" position only works in an entirely elastic scenario. It rarely works out that cleanly. London is a good example; wages are already extremely high in tech - to the point that many companies cannot hire. But supply is still not there, for a bunch of different reasons - e.g. people unwilling to continue/make a new life in the UK due to Brexit. Wages would have to rise _even further_ to offset that, way beyond the point it makes economic sense for a company to do that.

You can have very high prices and still insufficient supply. The prices are supposed to attract supply; but e.g. when a country is not seen as being welcoming to immigrants (or, in fact, has legal restrictions in place) the only flex is in people training/retraining, which is a many-years response to an immediate problem.