I think that sooner or later someone would have bumped onto the concept either by chance, careful innovation or just trial and error.
The McDonalds brothers themselves started franchising before Ray Kroc became a stakeholder in the business. They were however far more conservative than he was and consequently their nationwide expansion would have been slower, perhaps slow enough to lead to a more fragmented and competitive market overall.
Ray Kroc was a genius in the sense that he implemented very simple and yet very effective principle which made the chain successful. Simplicity, costumer service, cleanliness and chiefl friendliness among others.
They sound very simple, but a lot of corner Fish and Chips shops in the United Kingdom don't even apply them for example especially as far as consistency and cleanliness are concerned.
If McDs expansion abroad is far slower, then an overseas competitor might emerge. I always find it fascinating that a franchised chain of Fish and Chip stores never started off in Britain for example.