The polls all have what they call "margin of error." They always report that. And remember, the Democrats won the popular vote. So in that way, the polls were right.
It's like the weather. The media reports the weather forecast. They say it looks like a big storm is coming. Then at the last minute, there's a change in atmospheric pressure, and the storm blows off to sea. Or they say they expect a few inches of snow, and instead we get two feet. That's just what happens with the weather. Do you shoot the weather forecaster? No, of course not. That's what we have with political reporting.