If anything, it very well suits PiS supporters: they know what they think is the right direction and they will continue to go in that direction no matter what and they will not listen to any views other than ones from fellow PiSites about what to do. Which is why they will never again be involved in government.
If anything, they've gone so far that they won't even consider alternative views other than the currently accepted orthodoxy. Even the loss of Ziobro did nothing to dampen their faith in the Dear Leader!
But again - the circumstances of 2005 cannot repeat themselves - not even the most dodgy right or left wing leader would consider coalition with the mentally unstable Kaczynski these days, particularly after how he dealt with Lepper.
c) That was before the electorate knew what PiS would be like. Now they do.
PiS before the 2005 election were much much more moderate than now. If you go back and read the news articles from then, you can see that they were expected to go into coalition with PO, such was their moderation. Unthinkable these days.
PiS would need to get at least 45% of the vote to form a government (as they cannot form a coalition). They won't get more than 30%, probably less as they'll lose voters to SP.
It would be a remarkable achievement, especially considering that the polls are against them.
It's more likely that PO will win a majority outright than PiS winning, to be honest.