Polling is flat out unreliable. El Sayed was ahead of his primary opponent by 15% a week before election day.....he won by 1%....
People right of center don’t answer polls.
And kamala harris was +3....in Iowa!!!
And, he would have lost if there had been no third candidate.
Summertime polling is VERY unreliable. A large chunk of the country is on vacation and not answering polls. Plus internet polling is unreliable.