I know you guys prefer to believe your conspiracy narratives, but in the real world the polls are not fixed. Each makes different calculations regarding "likely voters" and they make adjustments to the samples. That is all. The LA Times poll, for instance, is a "tracking" poll, which means it contacts the SAME people every time. Not too many others do that.
Pollsters want to be right. That is how they make their money.
But, as always, explaining stuff to board zealots is a waste of time.
And good luck with the "undercounting" hope-against-hope. I'm sure that'll pay off.