Also the OP suggests they have the 1 resources, 2 ability to design, and 3 infrastructure to create an ASIC chip or finished product. That's seems like a far fetched assumption to me.
Just my 2 satoshis.
You're kidding, aren't you? All 3 of those companies have 1, 2, and 3. I'd say it's an uncertain market, that's definitely 1 reason the majors don't get involved. Also market size. AMD and nVidia might have a little interest, if they were sure the market would last a few years. Intel would consider the market way too small, even if they could have 100% of both sha256 & sCrypt sales. They probably make way more on just their LAN chipsets.
ASICs will be the realm of small, fly-by-night companies for quite some time. Notice how quick the prices drop? What successful company wants that?