One core intuition here is that as the safe return goes to zero, capital taxes are not especially burdensome compared to consumption taxes. Of course "the safe return" may not be entirely well-defined within a corporate context, and capital taxes often hit returns to risk as well, so this is a bit more complicated than the abstract alone would indicate.
The authors also offer this intuition, which I do not quite follow:
One of my biggest worries about a wealth tax is that it takes resources away from people who at the margin seem to be good at generating extra-normal returns. That comparative advantage might be more important as the safe rate goes to zero. So I am fine with the conclusion of the authors, but not sure if their intuition is equivalent to mine (I suspect it is not).
This one is clearer to me:
Overall this paper is very interesting and thought-provoking. Nonetheless, until we understand better why the safe rate of return has diverged so radically from "typical" (but still risky) corporate rates of return, I am not sure what implications we can draw from the model.