AAA batteries don't have the current. Li-Ion is too fussy and has a pretty high self-discharge.

Ukraine can afford the cardboard boxes because they are fighting in their own country. The US has an ocean to cross.

Ukraine can get away with short shelf life because they are at war right now. The US has to stockpile because the supply chain has to run at some capacity in peace time to be able to ramp up quickly when needed, and discarding the produced ammunition after a year would be incredibly wasteful.

Neither Ukraine nor Russia can defeat each others' air defence networks. The US has a lot of experience doing just that, while successfully defending against ballistic missiles. High tier capabilities matter.

The Patriot in 1980 is a very different system from the Patriot that is fielded today. Between PAC-2 and PAC-3, AN/MPQ-65A and LTAMDS it's a cutting edge air defence system. The progress is constantly incorporated.

The Stinger is a bit old, but mostly because the US doctrine has few uses for it. Regardless, NGSRI is coming.