There is really no evidence that lying has been the problem and not:

1) Response rates progressively plummeting over the last few years.

2) Traditional turnout models being wrong in such a high turnout election.

3) Pandemic hurt polling reliability (Democrats more likely to have stayed at home, thus more likely to have responded to polls)

4) Immense increase in political engagement hurt polls (Democrats have become very politically engaged in the last year, which means they are much more likely to respond to polls whereas traditionally polls expect a more even distribution of engagement)

5) Diminished trust in institutions which led Republicans to be less likely to respond to polls (which is different than pollsters being lied to).

There's still a lot to sift through to do a polling post-mortem, but the "systematic lying to pollsters" theory doesn't have much to it at the moment. Unfortunately, I get the feeling that it's going to be repeated ad nauseum for the next four years.