Great observation. With that thought, it seems that while too much information may kill a one-page site, other unwanted issues may arise by having
I'll also point out that single page websites are a little bit the flavour of the month and it's worth spending some time to figure out if that's exactly what you want. Sometimes you end up with sites that are simply too long, take really long to load, convey way to much for a single page and can actually be harder for people to navigate if they aren't thought out well.
Okay. I think I have a very specific purpose in mind for this approach: a "sales", "event registration", or other "promotion(al)" type website, specifically. More clearly, something that is designed to convert visitors.
Having said that, with the right site content and creative it's something that can potentially work very well, just make sure it isn't done because "the client saw it somewhere and now they want it" :-)