Interestingly, reversible USB-A cables are readily available (at least here in Japan). They just have a too-thin "lip" in the middle which is prone to breaking. https://www.sanwa.co.jp/product/syohin.asp?code=KU-RMCB2W
I think it's just that nobody thought of it when the plug was designed, because this wasn't a problem that serial cables etc before USB-A had (and even USB-B is keyed!)
Interestingly, reversible USB-A cables are readily available (at least here in Japan). They just have a too-thin "lip" in the middle which is prone to breaking. https://www.sanwa.co.jp/product/syohin.asp?code=KU-RMCB2W
I think it's just that nobody thought of it when the plug was designed, because this wasn't a problem that serial cables etc before USB-A had (and even USB-B is keyed!)