I always thought it had to do with chaining flags. For example, if multi-character single-dash flags were supported, and you wanted to write a `-lah` option for

I always thought it had to do with chaining flags. For example, if multi-character single-dash flags were supported, and you wanted to write a `-lah` option for `ls, you wouldn't be able to or else you'd introduce ambiguity. And nobody wants to type `ls -l -a -h`.