Polling has a lot more issues in 2024 than it did in (say) 2000. 1) What's the demographic of someone who answers a phone call in the middle of the day from an unknown caller? (Hint: they tend to be older) 2) Sample sizes of different demographics are too small for statistical significance - you might only get 3% of your data from black voters (4 responses), but since you know that demo is 22% of the voting population you just multiply your results by 7 - rendering the results useless. 3) Always a matter of turnout - just 'cuz someone says they will vote one way, doesn't mean they will actually follow through and cast that ballot.
In many ways, this last one is the most important. People who said they would vote for Hillary wrote in "Micky Mouse" when it came time. If 90% of the registered Democrats showed up to vote against MTG in her home district, she would be out of a job.
We are used to precision in our lives, and polling just isn't a precise science.