It's a shame for any open source project when people who formerly got to work on that project all day for a living have to go find another job. But big companies must keep their shareholders happy by relentlessly focusing on the bottom line, and even a two-person team -- tiny by Microsoft standards -- eats up cash. Ironically, smaller companies with vision (and, sometimes, indulgent venture capital) can often better afford to fund projects they truly believe in.
Last year, in an episode not dissimilar to this one, the two developers working for Sun/Oracle on JRuby, the Java Ruby implementation, jumped ship to the much smaller Engine Yard startup. And Ruby on Rails, the Web application framework that is the premier Ruby app, is thriving under the aegis of 37signals, a company with fewer than 30 employees that puts Ruby on Rails at the heart of its main offerings. The lesson for small projects may be that it's better to be a small company's heart and soul than a big company's PR move.