For homeowners in London, New York or San Francisco, this is all excellent news as long as they plan to sell up some day. Sky-high housing costs mean that more of the gain of new job creation is captured by landlords (or homeowners who get out) than by employers or workers. Technology has raised the return to living in high-skill cities, but has done nothing to make it easier to find a home there.
what is the meaning of the phrases in bold?
what does 'it' refer to?