ST angles, to a large degree, were determined by available lugs. Or the other way around, lugs were designed around ST angles that worked well. At any rate, if you're building with lugs, you've got a narrow range to work in. Now that many custom builders TIG, the constraints of lugs are gone, yet the standard angles still abound.
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If someone tells you that you have enough bicycles and you don't need any more, stop talking to them. You don't need that kind of negativity in your life.