"H2O after sitting on a shelf for 10 years turns into what??????????? "
The issue is not what it turns into, but rather that the bottlers are not trying to package lab-sterile water
for long term storage
. They expect that with normal handling and normal cleanliness, there will still be some bacterial growth and other good stuff in the water, and typically put a 2-year "use by" date on it. I've seen threads of "stuff" in old bottled water. It probably is still better than the pond water a dog drinks, but who knows what that stuff is?
OTOH if I wanted to put the water away long term, I'd open the cap and add a drop of iodine or bleach or other sterilant. (Yeah, more toxins, what else is new.)
Club soda has various salts added to it for flavor, seltzer is simply carbonated water. In either case, the addition of the salts or the carbonic acid formed by the CO2 *might* actually keep it tasting fresher, or discourage stuff from growing in it. And might also be a problem as it would change the pH and adding to stomach acids in a life boat
...might upset blood pH as well. (Any doctors in the house?)
So, the worm is in the tequila to prove it has killed bugs and is sterile enough to drink? <VBG>