There's another possibility, you know. Those long-haulers who supposedly did not have COVID might have had it fairly asymptomatically, and because the case was mild, it just took a long time for their bodies to develop the syndrome.

There are also false negatives -- LOTS of false negatives in the early days of the virus, before the tests got better.

The rapid tests still give a lot of false negatives. Some test sites now give you a rapid test but you also have to have a PCR test (swabbed at the same time) to make sure it's really a negative.