[roncesvalles]

None of the limitations of open-source licenses apply to the authors themselves. (author = the person or organization whose name appears in the copyright notice). I.e., you can have a MIT/GPL/AGPL licensed project, but have a "premium" fork/derivation/later-version of it that's completely closed source.

I actually see this as a valuable incentive to open-sourcing under MIT -- if a commercial provider of your software emerges, it will help you test/prove that a commercial market for your software exists, after which point you can completely close-source it and pivot to purely commercial competition.

Open-sourcing, then, is basically baiting the waters to see if anyone sees commercial potential in your work. And the minute that's validated, you get funding and start your company.

[zelphirkalt]

Close-sourcing a previously open source project is like a deathwish for that project. Will meet much aversion, and if the project is important, people will fork whatever the last open source version was. Then you usually lost all cards and don't have a business at all.