A more sustainable business model would be, I think, the safe middle-ground for both the consumer and the developer-- the Atlassian model. Offer an absurdly cheap .jar/.dmg/.exe out of the box which you can run locally for the end-user/small-business (what is it like a dollar a user a year for the self-hosted binaries?) and limit it to 5 or 10 seats. If the acquire-hire-kill by GoogAplTwitSquare happens, you still have a local copy of your data and the ability to migrate off the platform. If >(5||10) employees are using the application as a critical component of your business, making the seat-fee price-jump at that point is worth it (value provided > cost of seats, even at a few hundred dollars a month).
I'm hoping that sandstorm or another hosting provider that makes a business out of reselling open source anyway can try out one or more models where a fraction of the revenue is fed back to the creators / the community to encourage more development.
Don't know if it would work but I can hope.
Hopefully most should see some value in getting their software in the hands of more users while also getting a little money without doing anything extra.
I've started building a prototype of this idea using PouchDB/CouchDB (data is stored locally in PouchDB, synced to your own CouchDB server or Cloudant). As with most of my side projects, it remains abandoned waiting for some love.