It's bizarre how common that sentiment is among the MAGA crowd. I've personally heard people say it and I know plenty of others who have had similar experiences with them. It's always some variation of:
"There's no way Biden could have won! Everywhere I looked there were Trump signs and I ain't done seen a single sign for Sleepy Joe nowhere. It don't make sense!"
Well yeah, Jimbo for one thing most people don't make a political candidate their entire personality the way you bunch do. But it's probably also got something to do with the fact that you haven't left the podunk town you were born in since your Senior class trip to the state capital in 1976. Trump has always been massively unpopular. It's why he lost the popular vote twice.
Probably also because a lot of normal Americans are not only voting against little d, but also don't want to be a target of the violent magoos, so don't necessarily broadcast their house as one voting for Biden.
I've noticed these same rocket scientists seem to think that Biden was "campaigning from his basement" and that crowd sizes matter at all when it comes to casting ballots.