True, but some are not. Samples with likely voters are more reliable than registered voters which are more reliable than random adults. But when you see them all trending the same way, then you might just have something, especially when the explanation makes sense.
“Most polls” is my statement ,, not all perhaps ,, I realize there are credible polling sources but most media polling is as corrupt as the day is long . Even Fox cable has it’s problems with their “fair and Balanced” effort ,, with all the lib bloggers hitting them like a flash mob as soon as they go up . If likely voters in all 3 parties D’s , R’s and I’s are equally represented then you got a shot of a fair resulting poll . How often does that happen ???