How do the science and math papers use characters that aren't in... ASCII? Maybe I need to look at an ASCII chart.
Out of curiosity, isn't UTF implementation much easier now than it has been? I piddle in writing things and I rarely contemplate UTF. Once I tried to reverse engineer an encryption plugin that used Asiatic characters as the ciphertext, and I wanted to use emoji, and that was when I learned I am too dumb to understand utf. But there's libiconv, which I first saw in production (ICQ or aim or Trillian or so) over 22 years ago, personally.
So is the latex thing obstinance, technical, or political?
Sorry you need to catch up! The latest LaTeX engines (LuaLaTeX) can even do unicode math! But yes the Unicode spec s not something one can understand in a few hours.