FWIW, my CYA of 50 vanished between October and June. Since we are suggesting aliens and infections, how about a nice conspiracy theory? The chemical companies engineered the stabilizer so it would expire and we would all need to go buy more.
Also, I'm not ruling out overuse of antibiotics leading to resistant strains of bacteria that feed on CYA.
Also, its Trump and/or Obama's fault. (take your pick) Mod note: lets not go there please LOL