What does it mean when the facts on the ground bear no relationship to the polls?

Bookworm observes,

Something is very rotten with the polls. Trump draws 10,000 people to a rally; Hillary draws 100. In areas where their cars won’t get smashed up, Trump supporters have Trump bumper stickers. Here, in the San Francisco Bay Area (Hillary country), there are no bumper stickers. Nor is this because people are so secure in their votes that they won’t place bumper stickers on their cars. In 2008 and 2012, uncountable cars were festooned with Obama stickers, while I saw innumerable Bernie stickers during the primaries. Now, though? Nothing.

And yet, the polls insist that Hillary is creating an insurmountable lead. So one has to ask, what does it mean when the facts on the ground bear no relationship to the polls?

This isn’t just me being paranoid. A lot of people are thinking there’s something extremely rotten in Media and Polling Land.