I think I know what you're saying: times and times again, unknown people with no diplomas have found success in the tech industry. However that just means that it's possible to succeed without credentials or education.
But that doesn't mean the industry doesn't care about them. Look at how many stories mention "founded by ex-Googlers/Facebook", "YC-backed", etc. Sure, these are just from tech blogs, but if they add it in there it's because the readership reacts to that information, most often positively.
Besides, I don't think any industry doesn't care about credentials, since at least someone's reputation is their credential. For example, I don't know much about John Resig besides the fact that he created jQuery. That fact would open him many doors. It's not about education, but it's still credentials. Don't you think YC would instantly back him?
More to the point, I'm totally convinced that adding "YC-backed startup" to your resume, even if said startup never really went anywhere, is a very strong credential in a lot of places and I wouldn't be surprised if people use it that way. I'd even say that I'm sure many YC applications are "YC or nothing" in that if they don't get in, they won't start a company. It doesn't hurt to apply but the upside is fantastic: you get access to a great network, media coverage, some automatic seed money… and that YC stamp you can put on your resume.