Really? Because I remember:

• Hillary up +4 in the polls in the final count: https://projects.fivethirtyeight.com/2016-election-forecast/national-polls/
• Hillary actually winning the national vote by +2.1 (within margin of error of above): https://en.wikipedia.org/wiki/2016_United_States_presidential_election
• James Comey informing Congress about additional Hillary emails on Oct 28; too late for many polls to absorb the information. These emails turn out to be nothingburgers.

People learned the wrong lesson from 2016 polling.