Not an issue of being cynical -- it's just a fact that C enjoyed no "visible backing" from AT&T (or did you have some other corp in mind?) to help it gain mindshare, and neither did C++.
If "backing from multi-billion dollar corps" mattered as much as you seem to think we'd all be using PL/? or maybe some APL. Or do you forget who DID back _those_, and how much Big Blue dominated the computer scene until not-all-that-many years ago?
No, I don't think backing matters much at all to how a language becomes popular. C and C++ and Java have both popularity and the backing of billion-dollar companies now, and big money wants to play with big money. This becomes very relevant when considering how big shops make adoption decisions: a small money player has an uphill battle even to get noticed. Programming languages, databases, web content management systems -- I don't care, it's all the same. Big shops want their suppliers to have deep pockets. Little shops can be more flexible, but a lot of them just copy what the big shops do. The only reason C got into big shops is that American management is so incompetent it didn't notice what kinds of risk the hippies in the IT department were taking <0.9 wink>.
give-the-psf-a-billion-dollars-and-we'll-put-it-to-the-test-ly y'rs - tim