Korean also suffers from similar issues, where it's a bit more ridiculous: the textbook version of "polite" 2nd singular pronoun ("dangsin") has fallen so low t

Korean also suffers from similar issues, where it's a bit more ridiculous: the textbook version of "polite" 2nd singular pronoun ("dangsin") has fallen so low that it's pretty much an insult now, and no other term has taken its place. As a result, modern Korean arguably does not have a polite 2nd person singular pronoun. We somehow make do - it helps that Korean allows just omitting pronoun when the context is clear (same as Japanese).