No, cause it would then be called “Parby’s”

Well, if they call themselves “Arby’s”, that itself implies roast beef doesn’t it?

No, as far as I understand it, that's a common myth - it stands for the founders, the Raffel Brothers

Yeah, I’ve heard that but it’s always seemed a bit suspect to me
considering their history and the course that their business has taken …
… but what do I know about fast food? Not much.

What do you mean?

I have no idea what rostasi means.

In the 60s, the only sandwich they served was roast beef because they wanted
to be a fancy version of burger joints. Even their prices were way over the top.
Commercials often emphasized the "R" and the "B" and the love of "tasty
roast beef" (they used to call it "the 4-hour sandwich"). Later, there were
roast beef variations (with cheese, etc). When it was clear that that approach
wasn't working, they started adding other things in the 70s to fill out the menu
with some variety. All in all, it took a massive nosedive later even after giving
in to the temptation of having the items that other fast food joints were offering.

So, the fallback on the idea that it was named after the brothers is a bit
disingenuous since they rode that roast beef pony pretty hard during the early days.

This seems like a chicken and egg situation

Yeah, it could be seen as that -
or a convenient coincidence.

America's Roast Beef, Yes Sir! was another of their slogans back then.
I don't know if that's an acronym inside a ... ________
(what do you call a word that sounds like the initials of something else?),
but it was part of their early ad push.

I attended a lecture on the nature of conspiracy theories at my city's Center For Inquiry last night, followed by a gathering at a nearby tavern with the speaker and attendees. It was fun.

Now I'm wrapping up buying a brand new furnace and fixing roof leaks to get the house in good shape for the winter. It feels good to be productive.

Spending a quiet Saturday in bed with my circumaural cans spinning classics of the downtempo / deep house / future jazz scene from the turn of the millennium.

Simple pleasures.