Want to know why there's such a disparity? Because some companies are good at hiring, and others suck and don't realize it.
Want to know how to separate the good advice from the bad? Look for good companies and learn what their practices are. Find out how their organization works. If they're a lean mean innovation machine that values quality work and ships amazing products at a maintainable scale, chances are better that their hiring practices are also good (so long as you evaluate them before hubris poisons the hiring process, which may or may not happen). After you collect enough data points you'll probably notice a number of similarities.
In the end, the proof is in the pudding. People can opine till they're blue in the face, but if they're not killing it in their chosen market, if people don't really like working there, if someone is about to eat their lunch, then they're doing things wrong, and it would be risky to take advice from them.
Some companies succeed in spite of their engineering teams, and some companies succeed because of their engineering teams. What exactly is a good company? Is a great engineering team backed by incompetent management a good company? Or what about a company that has the full package but is unable to mail out paychecks on time and has a HR department that runs off anybody who exhibits an iota of independent thinking. It's really hard to say until you really meet with the company and spend some time there... and even then it's imperfect.
That's why I said "innovative, ships products, ahead of their competition, AND people like to work there". You can't get all of that without a quality, cohesive team covering many disciplines. And a bad hire into such a company increases the danger of derailing things. Thus, it's in any good company's best interests to carefully iterate and improve on their hiring practices, and any company that survives a long time with all of that intact is probably doing a lot of things right, including hiring.
Want to know how to separate the good advice from the bad? Look for good companies and learn what their practices are. Find out how their organization works. If they're a lean mean innovation machine that values quality work and ships amazing products at a maintainable scale, chances are better that their hiring practices are also good (so long as you evaluate them before hubris poisons the hiring process, which may or may not happen). After you collect enough data points you'll probably notice a number of similarities.
In the end, the proof is in the pudding. People can opine till they're blue in the face, but if they're not killing it in their chosen market, if people don't really like working there, if someone is about to eat their lunch, then they're doing things wrong, and it would be risky to take advice from them.