Yeah, the USA magazine (RIP) was a casualty of the USA's geography. The logistics of shipping magazines across an area that wide makes if astronomically more expensive than in a country the size of Japan.
If over 1/3 of the population of the USA lived in California, that's Japan in a nutshell. Sure California is still big (as states go), but if it had 126 million people living there, that's a very densely populated location. Mags wouldn't have to be shipped nearly so far, nor to anywhere near the number of different locations as if they were serving the entire continental USA. So the publishers can afford to publish their mags without as much dependence on ad revenue.
Also, unlike American mags, Japanese magazine publishers are the same publishers making all the strategy guides, and most times, the games as well. So a mag like Famitsu, published by ASCII, and later Kadokawa (which publishes almost all Japanese game mags still in print today, and has its own games division as well), is full of all kinds of cross promotion. They can write about the games that their own company publishes, and also print multi-part strategy guides in their issues for those games, which they can then collect in book form and publish as separate strategy guides as well. So you've got games, magazines, and guides all made by the same publisher - it makes keeping your mag in print way more feasible, even without the previously mentioned advantage of Japan's geographical advantage.