Homebrew may be a wonderful product, but that doesn't make the creator a wonderful engineer. Useful things can be poorly created. And this is not to shit on either Homebrew or Max Howell. I personally do not know if Howell is a wonderful engineer or not. He's obviously competent enough to ship working software. That's not nothing.
And everyone has an idea on how to improve everything. Sometimes we're right, sometimes we're wrong. And even when we're right, it doesn't make us right all the time. You can't really select for "the ability to create things that people want to use". No one's track record is flawless. It's very nearly a crapshoot.
Basically, you're putting Howell on a pedestal, in much the same manner you're accusing others of doing so with Google employees.
I think traveler01 does have a valid question. Essentially, with all of their engineers, why is Google so limited? And I don't think it's a matter of not being able to ship stuff that people use. Google Drive, GMail, etc. They just don't seem to be able to monetize beyond ads. Maybe their fault isn't in pure engineering.
And to be fair to the hiring process at Google at the time he interviewed, Google was an "all yes" kind of place. If anyone had any sort of hesitation, that could cause a candidate to be rejected. Their philosophy was that it was better to reject a good candidate than hire a bad one. So all he had to do was have one off hour, and that could have killed his entire interview. I personally don't think being rejected by Google's hiring committee is a mark against anyone. To get even that far requires a certain level of skill and/or talent.