Great points. Certainly aware of the open source nature, and ability to clone and run an instance, but for some organisations that's not really an option — they need a turnkey solution that has a somewhat inelastic dollar value and the ability to outsource all of the administration rather bringing another project in-house. That or they don't even have the technical human capital to support even rudimentary development work (there are TONS of Small to Medium Enterprise that would fit this bill).

I think your idea of private instances might be something worth exploring. It allows you to stick to your word, and the essence of the product while still finding another way to monetise.

Of course, if none of that seems interesting and you'd rather leave that problem for someone else to address than that's totally fine too. I only suggest it to you as you're already looking at the solution from a technical standpoint, and validated the need (based on traffic and use), indicating there is a market there to be serviced.