How long does unopened, room temperature pop last?
It lasts indefinitely. The date you are seeing should be viewed as a "best before" date. Over time the soda can become flat and the flavor will degrade, but it will still be drinkable as long as the can was not compromised.
Based on looking at some Coke I recently purchased, it appears that the date is likely 1 year in the future from when it was canned. The cans in my fridge have a date of
JUN1711; I bought these in late July.
Plastic bottles. on the other hand, have a much shorter "best before" window. This is because the plastic bottle leaks the carbonation much quicker than an aluminum can does. I don't have any bottles on hand, but if I recall correctly they typically have a date only 3 months out.
Once after a food booth at a craft show, my family had several cases of 7-Up (in cans) left over, and we decided we'd save them in the basement. Some time later (as I recall, about a year after the expiration date), we remembered them, and tried to drink it. It tasted horrible, and we ended up throwing it all away.
Also, plastic bottles leak chemicals (usually phthalates, which act as endocrine disruptors and may be linked to cancer) into the pop over time, and the rate of release accelerates over time as the plastic breaks down, which is another reason to want to drink pop in plastic bottles quickly or not at all.