I agree that paying fans have the right to complain. But please be reminded that they pledged the money voluntarily and some even knowing that the devs have other projects. If they are really unhappy with the progress, they also have the right to withdraw to give a piece of their mind to the devs. Or they can give constructive criticism, not whine about how long an update is taking and demand that the devs work faster and must have at least certain hours of content in an update.
If the devs are lazy / slow, penalize them. It's their own fault for not working hard enough, and they have no real obligations but ONLY THEIR OWN SENSE OF OBLIGATIONS to the fans.
The situation is similar to a manga. A mangaka can have many serialization going at the same time. But in the end, no matter how many assistants they hire, it's just one main source the content is going to come from.
This game is a collaboration, so it made sense to me on why they started a new page for the game alone. If I have a company and some other people comes to me for partnership into something else because of my certain skills, obviously I am not letting them into my current company but start a new one where everyone has a stake in it. So if this startup fails, at least it will not affect my other business. The rest bogs down to each partners' responsibilities to the company to make it a success.