As to why Japan isn’t always anime land, I could argue that anime does diverge a lot from real Japan. Sometimes in ways you don’t expect.
Anime blonds aren’t always tsunderes, delinquents, Westerners, half-Westerners, supernatural and rich girls though they often are. (Note they can and do intersect, in some cases perhaps relating to Westerners being rich or something.)
Naturally blond people do exist in Japan. Not just adopted citizens but also those with albinism. Bear in mind those with albinism are still Japanese citizens despite whatever misconception some of their compatriots make.
It doesn’t help that Japanese schools, until recently, suspected lighter haired students of bleaching theirs (actually not all Japanese who bleach their hair aren’t necessarily delinquents either). Some women actually bleach their hair to repel unwanted male attention.
I could go on saying that some Japanese people do dye their hair in odd colours (whether if blond counts) but it’s something that they’d get suspected for in school and head to jobs that tolerate these.
The Japanese spoken in anime’s the same thing in real life.
Somebody else already wrote about this. But that would involve realising how stereotypical most anime are (the more realistic anime do exist but not very common). There are some Japanese people who do speak like that, maybe not to the same extent. That’s how stereotypical anime can get.
To give a better idea of this, it’s as if US cartoons depict Southerners as speaking yee-haw even if not all of them do. Some of the X-Men comics are notorious for it, often depicting one character as saying ‘sugar’. Or any other dialect that has little resemblance to what those people actually talk like.