Sure, I guess “accident” is a vague way of putting it. I mean monospace sucks, but it sucked in a way that people could take advantage of until they relied on it. Now that we have ncurses, it’s hard to call it an accident.
I could complain the same way about practically anything. Cement. Unix. C. The genitive absolute. But granted that great things are made out of hacks, some hacks are uglier than others, and monospace is pretty darn ugly.