Same thing happened to Serellan and Takedown: Red Sabre. Contract with 505 Games ended, and so the original developer can no longer do anything about it as the IP belongs to the publisher. As you said Zips, the game isn't necessarily dead. Just means it's up to 2K to decide whether to end the game and sit on the IP, support development further in-house, or contract some other developer to handle the IP.

Not always a bad thing. Think of Tomb Raider and how it changed when Crystal Dynamics took over development after Core Design was given the boot (I've seen Core Design's interview, which I THINK is on Gamasutra, and how devastated they were at how their life's work was basically stolen with next to no notice from Eidos).

Still. Turtle Rock Studios didn't suck. So I wonder if they'll fund their own projects or if they'll look for publishers. Serellan did the former option (Epsilon), but the Catch 22 issue is that if customers don't buy the game at an early state, there won't be enough money to produce more content, but if you don't produce enough content (even with Early Access), then people will choose to wait and not buy it regardless of the price. If Turtle Rock Studios wants to have full control of their IP, then I'll be Captain Obvious and say I hope they have enough working capital to do so, without any customer purchases to support them.