I agree with that it's too early to tell, but I'm interested in how things will turn up to be like, for instance:
- Jolla won't need to sell millions of devices to be successful [in the short/mid term], so they can take certain liberties.
- Firefox is tricky since they are funded partly by Google... not sure how they'll expect money back from their Firefox OS, perhaps just licensing? In which case, how much do they need to sell to be successful and continue their work?
- Ubuntu: not sure about how big they are and what their success goals are. Again, they don't seem to be selling any device, so money-wise maybe it's just licensing?
- Tizen: I'm pretty sure Samsung will want to sell millions of devices running this for a certian period of time to justify their investment.

For what it's worth, I hope all of them will be a success and in consequence continue with their work, we certainly need more options rather than fewer. Will developers have to maintain more versions of their software? Well, yes, so what? It's been like that for years... maybe it will get better with standards, but for now that's totally understandable.