That is a very optimistic view of the future, specially if you think it will simply happen “just like that”, without any political fight. Really, to me it all sounds like 1. daydreaming 2. the far-fetched future. Nothing for us, or our great-grand-children. Besides, this whole article seems to be to deterministic (economic determinism), which is a problem — even disregarding the author’s opinions — where are the politics? Where is human action and interest in his assessment of the future of mankind. And this is only one of the problems…. now, I imagine if it is really possible that capital becomes “cheap”. In real life, we see it is not always a matter of availability, but of distribution: it doesn’t matter if diamonds are actually pretty common, we don’t have access to it because it is monopolized by a few companies, that make it expensive.
Overall. this all sounds pretty much like liberal daydreaming.