Where I live we still have restaurants that only take cash. There are even two places nearby where you can walk in 24/7, grab what you want out of their fridge, and put your cash in a box on the way out. Cash only can still work.

Where I live those fridges and the cash box would both be empty in a matter of hours.

Now imagine that instead of a local restaurant, it was a global conglomerate with restaurants in nearly every country

Look at the date on the article below. McDonald's grew into a global conglomerate well before they started accepting cards.

https://money.cnn.com/2002/11/26/news/companies/mcdonalds/