I know nothing about film, but I think it’s highly unlikely to happen with her publishers. RW arguably breached the standard contract in which she takes legal responsibility for the memoir being substantially true, but that book had made Penguin RH a chunk of money. They could decide to cancel On Winter’s Hill altogether and ask her to repay her advance, but if that advance was for a two-book deal of which Landlines was the first part, it makes things slightly more complicated, as that will already have partly earned out some of that advance.
Also, her books sell. As Richard Osman said on TRIE, TSP’s sales will have paid for a lot of other books that sold less well (though I imagine there have been diminishing returns with the subsequent books? I’ve only read the first two but TWS reads very much like someone trying to cobble together something to replicate TSP’s success.)
I think her publishers, having put out a holding notice by saying they’re delaying On Winter’s Hill because of the author’s ‘distress’ at the controversy, will just sit a bit and see where public opinion goes over the next while.
There might or might not be an appetite in a year for a much more apologetic, warts and all ‘We repeatedly fucked up with people and fled to nature’ type of book.
Or, if they have enough money to live comfortably, they may just continue to keep a low profile. There doesn’t ‘need’ to be another book at all, unless they are desperate to ‘put the record straight’.