There is not an "after capital" world. To manufacture anything you need capital first. Even for software services you need software, that's also capital. So to reach a world of post-scarcity you need a lot of capital.
Therefore I would read the title not as "after capital ceases to exist" but "after capital ceases to be as relevant".
Something worth considering in relating this to Marx is that while Karl Marx did not live at a time that would have favored a deep awareness of media, his work is very concerned with culture. His more economic terminology was "human relations" and how capital mediates human relations.
These days, what we call media ("mediation" of human communication) is at the root of our concerns with attention.
Having studied Marx, I assume my eagerness to relate his work to contemporary economics discussions might seem desperate but it seems desperate to me that others try so hard to do otherwise. I hope you'll forgive me.
Marx did live in a more simple time but the wonder of his work is that he identified so much of the forces that guide our society. Even living at a time when attention was at a surplus, his work is robust and thoughtful enough to translate in more modern times.
https://www.youtube.com/user/petercoffin
Most of his stuff is focused on how attention is used to manipulate people's worldview in the "Marketplace of Ideas", but his latest video is about considering attention as labour. (Although, I thought it was a little unclear tbh)
I would also add that the author seems to be talking a lot about the transition, so maybe it's not so much "we have enough capital now", than "we're getting there in a few years/decades", and hence the question about what lies ahead. Well, he actually writes that:
> Capital is already no longer scarce in some parts of the world and rapidly less scarce everywhere.
Rapidly is a very relative term in this context.
Since that ended, the industry has developed much more slowly in the absence of an obvious profit incentive. Indeed, even now, SpaceX has relied on collectively allocated resources from NASA for many of their contracts, not to mention all the research done during that period.
And in any case, SpaceX is still an example of prioritising capital creation. SpaceX is a privately owned space launch system, which will likely primarily benefit other privately owned space industries in the near future. We may like that this particular capital is being created, but it's only a small part of the wider economy.
Supposedly Lenin was able to meet Marx once before the latter died, and asked Marx about his opinion on bootstrapping Russia straight to socialism. Marx thought it a folly as the nation lacked the industrialization that Marx figured was a prerequisite.
According to Marx, capital is an accumulation of money used to purchase something so that it may be sold again AND whose consumption brings about an increase in the value of the commodity.
They definitely help you make money, but they don't have the special attributes that make capital so desireable--you can't sell it to turn it into another form of capital, and crucially you can't employ others to use it to make money on your behalf while capturing the surplus value of their labor.