I'm not saying that you are alone in your opinions, but for one, I think it's discouraging to say that the only jobs
non-Japanese, (& coincidentally, when you live in the United States for a week, you're not a tourist, you're not a "foreigner", you're a resident...) that the only jobs they can do is to teach English.
If you are trying to be a graphic designer in Japan, and you want to design cute things you think that Japanese will like, I think you're in for some disappointment at your prospects at getting a job, the same goes for being a game developer for a Japanese company... In some aspects of some jobs, you both are expected to understand the Japanese work environment, and not only that, understand your Japanese clients, however big that demographic is.
However, there are people, who for example, work as marketing analysts in Japan, granted their Japanese is superb, and it includes the lingo needed to speak about marketing trends, but they're non-Japanese just the same.
If you're moving to
Shikoku to find work, you're definitely going to have dimmer prospects than if you move to Osaka or Tokyo.
ps. I also know of living breathing people I have met in real life who have worked in an office environment, who knew keigo, who have worked in Japan. Some decided that the environment didn't suit them, for this or that reason, but these are real people, not my opinions, nor figments of my imagination.