I agree that Rails developers will probably still have plenty of work in the downturn. But, then again, Django & PHP developers may also.

However, I'm not sure I buy the argument that the work will come from corporate IT projects.

FTA: "First of all, while we fully expect some CIOs to delay or cancel some internal IT projects."

I agree–you'll see a lot of canceled and delayed projects. But, I think it takes quite a bit more to convince a corporate CIO to outsource the development AND hosting of an internal project.

Maybe I've been out of the corporate world for too long (it's been 8 years), but in my experience, a CIO would rather put a project on hold than a) get up to speed on Rails, b) put a project out to bid, and/or c) worry about the perceived risks of having corporate data on external servers (especially in the case of financial, healthcare, or edu entities).