There are three contingents right now. Facebook (SC2/Amber) wants to make rich web pages. Tilde (SC 1.7+) wants to continue the Strobe direction of deploying client side web applications in different contexts. Erich Ocean (1.4 fork) wants to go back to his original philosophy of creating applications that can be deployed on the natively or on the web. The primary break Erich Ocean wants to make is to drop templates and construct interfaces in the desktop / Cocoa style, not a mixed HTML templating one.
So there are still core folks working on 1.x, but in different contexts.
It is, but it's being fixed. I expect the situation to be __very__ different by JSConf 2012.
It's been clear where SproutCore has need to go since 2009, but there hasn't been the support to do that, due to the various personalities involved. Those people have moved on, and now SproutCore can do what it's good at: building fast, desktop-style applications that run in a web browser.
Things haven't looked as positive for SproutCore in two years. I pumped.
So there are still core folks working on 1.x, but in different contexts.