> That said: is racism a bigger problem in Japan than e.g. in the United States? Oh, yes. Unquestionably.
This is totally ridiculous. I lived in Japan for a year and as a white male, it was the first time I experienced being on the receiving end of racism. It sucked, but was a good lesson into how it feels.
Racism in Japan when you are white is not that bad. Ask your Korean or Nigerian friends in Japan what it is like and you will get a much different answer.
Not sure which London you've been living in (or visiting) but I would say there are many more choices than the three you outline above. I know many people here who work in startups/online media/web dev etc.
The one thing I will agree with is that it's not cheap. I think it is fair to say London is probably 3X more expensive than Berlin.