I mean, there's more to it than that. A friend of mine is a prominent head brewer in the Denver area, and a couple weekends ago we cranked the numbers and figured out that the cans for hard seltzer are more expensive than the contents (aka the actual drink) from a BoM perspective. A labeled can is something like 14 cents, and the contents were something 10 cents. For a can of beer, the contents are closer to 50 cents.

The margins are just stupid good. Apparently Upslope brewing here already makes more profit on their seltzer than all of their beer.