That's actually not keeping capitalism in a post-scarcity society, since the proposal relies on having existing (and artificially enhancing the existing) scarcity.
If anything that anyone wants is limited such that enhancing one person's realized utility is a trade-off with someone else's realized utility, you don't have a post-scarcity situation.
Which is why post-scarcity isn't really something we are ever likely to need to worry about.
What we need to worry about is a scenario with scarcity where large masses of the public are (some in a static way, and some in a transitional way that, with optimal policy, could resolve given time), through arrangement of capital and the relative utility of automation vs. labor (including when it comes to producing additional automated production units) unable to contribute significantly to output, and thus have nothing to sell in the marketplace.
