[vbuterin]

Co-author here. I definitely use the phrase "public goods" in the economic sense: goods that are non-rival and non-excludable.

This post has nothing to do with assurance contracts (which that paper seems at first glance to be equivalent to). Instead, it's tackling the different problem of what if there is some established mechanism that is already collecting fee revenue, and it wants to do use that revenue to support its wider ecosystem.