Consider the ride vehicles. How many of them could hold more than 1 or two people who are 6 feet apart? I figure, Test Track - one per car. Pirates, Splash Mtn (WDW), IASW - 2 per boat. Most dark rides and coasters - one per car. And the cars are moving. If someone coughs or breathes a cloud of germs, the next car will move into the cloud before it can disperse.
6 feet apart? That is old news. Current studies show 13 feet and the bottoms of feet/shoes.
If six feet was to be taken seriously, than 13 would be the actual suggestion.
And as you said
The six or thirteen feet rule on ride vehicles is pointless because the areosol drift with wind is said to carry a lot longer. Something like a coaster or swift moving ride vhicle like The People Mover, it would just be billowing to the next group.