@Herby
"If I were an OEM that was considering an embedded operating system, anything with the name "Windows" (or Microsoft) would be on the DON'T buy list for the simple reason that I would have NO CONTROL over it. "
I *really* hate saying this but before Linux there were a number of proprietary *closed* source OS's supplied for embedded use. Wind Rivers (Lynx?), OS9 (and to a degree Symbian)spring to mind.
What they did have were AFAIK a multi layered modular architecture (not one designed to intermix a proprietary browser to prevent it being untangled due to an antitrust case) *much* more stringent module and integration testing, more open interface specs (to allow developers to drop in their own modules seamlessly in) and an upgrade cycle normally in years, not weeks. The *whole* OS is a developer tool, and priced and licensed to match. End users are just *that* ,people who *use* it.
These companies know their market, understand their users issues (typically hard response time limits and tightly controllable possibly variable process priorities, which regular Linux is *not* AFAIK optimized for) and deliver a complete environment to support them.
People did (and AFAIK do) use them still. The loss of control due to the closed nature of the core of the code is offset by the better range of tools (who wants to write an Ada compiler?), faster time to market and the ability to focus on the core specialized features of a developers application without getting bogged down in the necessary but common bits. However what these suppliers have is the the *trust* in their customers that they do *not* deliver bug ridden, insecure bloated systems which are just waiting for the next virus infection.