While PCR isn’t good at picking up whether a “particular individual” is sick or even infected, it does seem to pick up elevated coronavirus particles at the population level during cold season. It cannot say whether any individual person is sick or had symptoms, but it can detect a population-wide elevated signal. Leaving aside the myriad possible interpretations of that signal, it is being detected. Coronavirus has always been with us, and at most it has been worse slightly in recent years. Perhaps they catered this specific virus to the situation, finding something that would peak in October-December for the 2020 Presidential Election?
All we can really take from PCR at any given moment is that it tells us, broadly, whether seasonal coronavirus is active within the population. Like back in the summer, when it basically wasn’t active anywhere, but we didn’t open the country back up out of…cowardice, I guess?