Warning: rant ahead which extrapolates from a single documented data point.
The simplest statement about the status of Rubinius is that there are now zero people paid to work on the project.
Many community-developed projects have corporate sponsorship. A lot of projects have companies which support the software. Others have foundations to handle donation. Still others have a loose alliance of consultants whose contracts allow them to release some, most, or all of the code under free software licenses.
If you follow the Hacker News Daily Gosizdàt dispatches from VC-istan, you'll soon learn that free and open source software is how two teenagers can drop out of college and found the next multi-billion social network for dogs to share pictures of recipes.
Sometimes one of those actual successes will release software to the world as a whole (WebKit, LLVM, Go, HipHop (and, yes, that list is full of irony; consider the Google black hole of talent into which promising free software developers disappear and useful software fails to escape)). Usually the startup will implode into a neutron star full of self-satisfaction, taking with it tens of thousands of lines of unmaintainable code no one wants anyway. (Although the world really could use one more WordPress plugin for caching static requests and one more web request routing plugin for Node.js, but only if the latter manually parses HTTP headers.)
Even when a company succeeds at prying cash from the tech-necrotic hands of a venture capitalist (usually involves sacrificing your soul, or at least controlling equity), that sudden influx of resources usually doesn't make it to the underlying technology that helped that company build something to separate VCs from money.
(You'd think the class of person which helps itself to shiny new Macbooks and iGadgets every year because they "deserve high quality engineering in [their] tools" would throw a bone to the software they use as alternatives to stacks from Microsoft and Oracle, but I've only known one startup which went so far Apple as to deploy to Mac mini servers.)
Maybe that's okay, but maybe funded startups are vampire squids which take advantage of free and open source software without doing much to ensure that it survives longer than their doomed startups.
Startup culture has never been efficient; the business model works if there's one huge hit and a couple of moderate successes for every couple of hundred failures. Free software is different. The business model works as long as there's someone willing and able to release new versions of the code (even if that new version is merely a packaging improvement or a one-line bugfix or a correction to a typo in the documentation).
Unlike a startup, community-developed software is not necessarily beholden to customers or even users. It is beholden to the interests and abilities of its developers. If that interest or ability wanes, the software may not survive. (The code will still exist, but will it persist for long in a usable form? Who knows.)
It's well and good that startups can build themselves ever more cheaply and well with software released under free and open licenses, but if they're not contributing back to that software somehow after they've built successful businesses, they're cheating themselves (and the next generation of businesses).
After all, a business which has the revenue to support a dedicated sales force is probably foolish to use word of mouth as its sole advertising and sales strategy. Why should we consider it any less foolish to use the time and interest of unpaid volunteers as its technology infrastructure strategy?