I think there's some confusion here over what jdietrich meant by "Success is not validation of an idea." He was merely pointing out that just because a product is successful (i.e. everyone buys it) doesn't necessarily mean it's a good idea (i.e. a net positive contribution to society). It may be a good idea, or it may be neutral, or even potentially a net harm (such as in the case of cigarettes). He's not trying to redefine success, he's just saying it shouldn't be the only consideration when judging an idea.

I think we can at least agree on that point.

Side note: I'll admit that there is no single objective interpretation as to what actually constitutes a "good idea," which further complicates the issue. I just figured "net positive contribution to society" was general enough to make my point.