This is a terrible form of argument. Success does not mean you're correct. Many successful people and things deserve criticism. I don't think DHH or Rails is among them, but that isn't because they're successful.
Err, yes, it does. That's precisely what success means. If you are successful at something, that means you did something right. What that something is is certainly up for debate, but you can't ignore success as an argument.
Right; for example if you're a successful pharma CEO you might be able to afford the one and only copy of a Wu-Tang Clan album.
Unless you define "success" as "being rich", no, I'm sorry, it's not true. It's actually quite easy to become rich by being a complete scumbag with no consideration for other people.
I think a much better, more relatable, and currently very striking example of this fallacious "rich and famous people must know what they're talking about" line of reasoning is the current U.S. Republican presidential primary front-runner.
