Yeah, weird how they didn't even explain that in the article. Oh wait... they did!
He never said they didn't explain it, he just said it was weird. Despite the explanation it's still weird that Japan is a single entry. There is just as much reason to at least give Tokyo a separate entry.
I don't think the explanation is accurate. After reading the article, I think the more likely reason is that the authors are just more familiar with the Bay Area than they are with many of these other places. The Japan entry for example reads more like something copied from tourist literature. Here is an example:
it is also far more advanced in a number of areas such as gaming consoles and
smartphones.
Anyone familiar with Japan and the consumers there would know that Japanese Smartphones are not more advanced, most of the popular and advanced phones are not Smartphones but clam shell phones with numeric key pads. In fact most of the actual smartphones you see in Japan are not Japanese, they are American or Chinese. I'm not merely trying to correct him, just point out that the real explanation probably has a lot more to do with the authors having token incorrect information about some of these other places and having first hand info about the bay area.