

Coca-Cola atleast some plants have blow molders for plastic bottles. Making cans is a massive ordeal and requires its own plant, so if they have the space they could probably do it as well. A plastic blowmolder is under 100sqft. Makes more economical sense to ship in blanks and make your own than shipping 10x empty air volume.
You realize in general means not in every case? In Canada and the USA, that’s not the case, they make their own syrup and fills cans and bottles.
Sure other countries may outweigh it, but large countries don’t operate that way.
Source, I’ve installed blow molders for bottling plants that mix their own syrups.
They have multiple lines, usually one for pop machine, two for plastic bottles and one for cans. Depending on the size and location they may also distribute stuff like Monster as well.
Now if you’re talking like a small town somewhere, shipping syrup is cheaper, so in specific cases (not in NA) it can make some sense to ship syrup and then add the water.
Pepsi-co more or less operates the same as well, they have blow molders on site for plastic bottles.