I strongly disagree with this non-sequitur. The fact that we have achieved some level of material success now doesn’t mean that the future opportunity isn’t very large. Again, Chamley-Judd is the classic result in the space, suggesting that it is never appropriate to tax investment for distributional purposes—if the latter must be done, it should be done with individual-level consumption/income taxation. This should be especially clear to EAs who are aware of the astronomical waste of potentially forgoing or delaying growth.
However, it’s very hard to get individuals to sign a WC for a huge number of reasons. See
The pool of potentially windfall-generating firms is much smaller and more stable than the number of potential windfall-generating individuals, meaning that securing commitments from firms would probably capture more of the potential windfall than securing commitments from individuals. Thus, targeting firms as such seems reasonable.
However, it’s very hard to get individuals to sign a WC for a huge number of reasons. See