Polls have not been off, theyve been selectively polling specific demographics.

The only way they were able to show Clinton beating Bernie in 2016

Gotta look at the methodology of the poll, usually at the bottom

For this poll,

Methodology This ABC News/Washington Post poll was conducted by landline and cellular telephone Sept. 15-20, 2023, in English and Spanish, among a random national sample of 1,006 adults. Partisan divisions are 25-25-42%, Democrats-Republicans-independents. Results have a margin of sampling error of 3.5 percentage points, including the design effect. Sampling error is not the only source of differences in polls.

With an even split between of those polled D and R, Biden is still losing