I agree. I think you can see the law of diminishing returns at work in TWS and LL.
TWS is an attempt to pad out a ‘what happened next’ narrative, with the missing year removed, SW’s mother’s death moved from its RL date, TW’s studies moved up, and a walking holiday in Iceland also stuck into a largely fictional timeline. It sold purely on curiosity about what happened next, and cutesy details like SW erecting their tent in the bedroom.
LL is her realisation that she needs to go back and echo her TSP USP, and try to replicate the two successful elements of the TSP brand — TW’s failing health and a long walk (even though the walk couldn’t be more different, because it’s a long holiday, bolstered by van collection services, hotels, taxis, GPS and ordering replacement gear online etc, and carefully ignoring the fact that they’ve become the people they sneered at in TSP, well-off retirees on holiday, rather than plucky, starving underdogs.)
We know that she was signed for a three-book deal after TSP, so she needs to crank another one out. Who knows why the rewilding at Haye book didn’t happen? Possibly BC was already too suspicious. Or she’d never really intended to write another book about Haye, and they’d decided to move on.
Either way, she needs material, and it’s not clear if the reading public can cope with another ‘he’s near death, lying in a pool of his own urine — oh, hang on, now he’s walking a 1000-mile hike and miraculously cured’ plotline.
Maybe it was going to be a glumwashing of fame and riches, and how all her speaker events were too taxing, and how all SW really wants is a pack on her back and a path at her feet, even if TW is now too frail to accompany her?