For better or worse, the balance of global commerce is rapidly moving to Asia. The US is no longer the only country capable of advanced software development, nor necessarily the most qualified (particularly in the embedded space).

I think the Eclipse Foundation sees more of their growth happening in Asia, and that's a lot easier to do from the EU as their working hours overlap with both the US and Asia. Working hours in Asia don't overlap very well with American hours; their most productive hours happen in the middle of the night for us.

I'm sure there are other reasons too, but these seem like some of the most practical.