FWIW Seth is actually talking about a bootstrapped company and not a venture backed startup. As it stands the software is already complete, and there are maybe ten thousand potential firms who are well-suited to buy licenses. They don't want to grow in any way, so at any given time there are only two things the founders can do that would create value: sell a license, or add a feature / improve UI. Because of this I think some variant of Seth's suggestion actually makes sense in this case, albeit choosing a split upfront and then vesting is normally a much more sensible way to go.