I've worked both in the Valley and in Seattle, and in my experience the startup mentalities have been pretty much the same. There may be a lot of former MS people working at the startup, but they don't seem to have any attachment to it. If iOS or Android are where the numbers are, that's where they go. I've also never met a startup in Seattle solely focused on developing something for MS, although there probably are some that exist. Whatever trend you saw in the northwest previously must have changed, from my limited perspective.