I've always been an avid reader and for as long as I've able to read I've always read multiple books at a time, depending on my mood, and I finish them all. Granted I didn't grow up with the massive amount of available media kids have today, but I don't see a problem with kids reading multiple books at a time, if they go through them anyway. I much prefer this than kids not reading at all.
I can see your point though, I just can't agree with the books part, from my personal experience.
Yeah, I grew up getting books at yardsales and used book stores, usually a dozen at a time for a few dollars, and I almost always read several of them at a time. Switching between books seems like a natural way to read books, it's not a symptom of mass media induced brain damage or whatever is being suggested above. My family didn't even have cable TV so I'm quite sure my attention span wasn't damaged by it.
I can see your point though, I just can't agree with the books part, from my personal experience.