It doesn't have to make sense

Look- it's simple! When you open a can of pop, what noise does it make? It doesn't make a noise that sounds like "soda". It goes "POP", ok? This makes sense, no? Oh, and in northern Ohio, we say pop, but everywhere else in the state says soda......hmmmm.....

We say coke down south. Everything is a coke even if it a Pepsi, sprite, dr. Pepper etc

In Australia it's fizzy drink or more commonly soft drink...

Its soda.

I don't say pop or soda. I say what the drink is actually called. If I want sprite I say sprite. If I want coke I say coke. I haven't heard anyone say soda or pop in a long time.

We say pop in Chicago

I use them interchangably