I agree about the time issue
I agree that most companies don't spend enough time doing interviewing. I have SOME insight into that... when I was heavily involved in hiring, we were ramping up the department so we needed to hire more than one person. We wouldn't get much filtering from the recruiters, and we had cast our net pretty widely due to lack of the right people locally. I was spending an hour a day reading resumes, many days I would spend an hour or two (or more) doing phone interviews, plus there would be a number of face-to-face interviews throughout the week. All said and done, the basic hiring process (before you even found someone you wanted for a second interview!) was consuming a huge portion of my week (as well as the other managers involved) with no compensating reduction in the rest of the workload, which was already a 50 hour/week job!
Under those circumstances, you can imagine that doing the Microsoft or Google day-long battery of interviews, tests, etc. just isn't possible. Maybe for companies hiring for just one position that is possible, or who do so much hiring that they have a massive staff of recruiters who have a locked down process to spare managers from the bulk of the work, but for you typical manager in a typical company... the time just isn't there, regardless of how important it is!
J.Ja