I've looked multiple times at dozens of stores. In my area of the U.S. they can't be found in stock.
Preparation is a thing. It was quite obvious we were likely to have a covid spike this winter. Anyone without a stock of antigen tests at this point has simply been irresponsible as it was trivial to buy a few boxes at $14/ea at walmart the past 6mo.
Abbott both destroyed unsold inventory (6-7mo from expiration dates) and closed down one of their production facilities they stood up for these tests due to lack of demand over the summer.
If everyone was a "prepper" (no, I don't think having some basic $7 tests sitting in your medicine closet really reaches this point at all, this is called "being prepared" and used to be a civic duty taught to children) the production would not have stopped, and they would not have let 2500+ workers go they are now scrambling to get back.
tldr; production was there, it was ended due to lack of demand. Yes, some (many) folks are in a financial position where $14 is a large expense, but those are outliers and certainly not the folks asking if I have any tests on hand right now.