I don't think that's particularly surprising. If what we'd call a standard mechanism today (like using an option) had been in use first, why would there have be

I don't think that's particularly surprising. If what we'd call a standard mechanism today (like using an option) had been in use first, why would there have been the need to change it to something that is done elsewhere at most rarely (special form of argv[0]) would have been introduced later?