I'm not saying it all has to be at the same time. In fact, that could be annoying because the hotshot candidate would hoard like 12 offers instead of the usual 5 or so. But as it is, the range is pretty remarkable. In the humanities they have the MLA conference that forces schools to be on a similar timeline. If all of it happened in the fall or all in the spring, there would still be a lot of leeway. But the fact that it takes all year is not really acceptable.
I don't think it's that fair to compare it to "real" jobs, because in other industries you're not pulled all over the country to random locations. In other industries it is more often the case that you can apply to jobs in a specific city or small set of cities more easily than you can in academia. Also, in reality the fact that you can start (and FINISH) a position at any time of year makes things more flexible, not less so.
As for having time to prepare for interviews, well I feel like most people don't get THAT many interviews, first of all, and secondly you typically give a pretty similar talk for each place. I didn't feel like it was that bad preparing for my interviews, and I had two around the same time as it was. If you're a grad student or post-doc, you are typically released from some job-related duties in order to go on interviews because it's expected, so it's not that big of a deal to be MIA for an entire month for this purpose. If you're already a professor then maybe not so much because you have courses, etc, but hopefully you're not applying to so many places that you'll have so many interviews.
As for people who don't get any offers, I think it is MUCH better for them for the process to happen all at once. If you're on the edge of your seat the entire year waiting for something to happen, you can't make back-up plans such as getting a postdoc or an adjunct position or looking for an industry job. Or, frankly, focusing on publishing so that you can hit the market stronger next year. If I were to be rejected from all jobs I'd like to rip the bandaid off at once. In fact I have some experience with this, too. Two of my top choice jobs actually did their process in the fall, and I was not interviewed. It was SO nice knowing about them early on so that I could go into my current choice (which I still like a lot!) with a positive and more confident attitude. It's just that there were other potentially better (and potentially worse) choices that emerged in the spring, and I'll never know about them.
And if the schools are going to spread things out, then they should at least go in rough order of competitiveness. But I feel like that is not the case. At least some of the schools who go early do it with the specific purpose to try to snatch up candidates who could have gotten a "better" offer later (I have heard about this directly from faculty friends with people at one such school!)