That’s a good presentation of history.
But it’s not the way to examine these things.
There has to be a known mechanism and that mechanism is turnout model. The only other way to bias a result would be to exclude neighborhoods from phone calls, and this is just not reasonable when sample size turns out to only be 800ish +/- 300. That is asking pollsters to know neighborhood makeup for not just area code but also phone number prefix. And that fails when some use online surveys.
So the only mechanism of bias has to be turnout model. Declaring this pollster is left leaning vs another that is right leaning does not explain why. How did they achieve the lean. It’s not by phone prefix. It has to be turnout model.
2016 was chockful of analysts (whose paychecks come from running a polling company) explaining loudly how data did not really fail. Data is still great. This was wrong because Trump voters refused to admit it. Well, no, because there is no reason to think Trump voters refuse to admit it in only certain states, and there were indeed states where the polls were accurate.
No. What happened was failed turnout models. The most recent Census was 2010. The party affiliation data was similarly very old. But whereas a pure academic exercise would have announced that there was no possible way to make an estimate, you can’t say that when getting paid.
This year, the Census is only 4 yrs old. The virus corrupted all information in 2020 so largely ignore that. There will be VBM, but the requests for ballots are way down this year vs 2020. And so, do not look at Morning Consult Harris +X. Look at whatever information (often not extensive) you see from Morning Consult on White/Black/Hispanic ratio.
Look, people see this data that says something like Women/Men 53/47 and declare women were oversampled. This isn’t true. Women 53/47 is the correct ratio given they live longer and there are more of them. Racial sampling is how the Harris surge was manufactured. The pollsters decided blacks would turnout more. They generally already turnout 65%+, about the same as whites, but by lifting them 2% to 67% and knowing they vote 80/20 Dem, you can move the needle.
That’s the conclusion. You can’t declare left or right leaning. You have to examine the turnout models. If they justify the model with source of partisan mix and source of man/woman, then it is not they who are biased. It is the source.
As best I can tell, everything you posted is correct and I wouldn't dispute you on it.
It may be that the only disagreement we have is over my words "left-leaning" and "right-leaning".
You point out that it's not political bias but rather the turn-out models which cause some pollsters to forecast more votes for one side than actually happened.
I'm only suggesting that a pollster's selection of turn-out models could well be biased by the pollster's own fondest wishes.
To pick a few examples, the following pollsters consistently overestimate Democrat turnout, every year since 2014:
On the other hand, if everyone already knows they consistently overestimate Democrats, then how do their polls benefit anyone?
So, it's... ah... "complicated", I'd say. 😉