If polls are wrong, it is in no small part thanks to changes in electoral sociology, living arrangements, methods of communication and media consumption habits which make it much harder to pollsters to get it right by using their traditional models.
We live more individually and less collectively than we used to. Opinion polling is based to a huge extent on the assumption that voter behaviour is driven primarily by the latter...
I don't think that quite works as an explanation as the most collective, 'rooted', etc section of the community in all cases afaik where the polls have failed are the older sections of society. And it's been their very solid vote for the Right, often underestimated by the polls, which is why the polls flopped here, in the US, in the UK... If it was great individualism that was the issue than you expect the younger vote to be underestimated, but that doesn't seem to be the case.
