Eh, mercedes never actually seemed confident about "knowing their issue". Even towards the end of 2023 Toto would throw up his hands and have no clue why their updates were not bringing the expected results. Merc was massively flattered by Aston's huge missteps, Mclaren starting with a frankenstein monster car and Ferrari started with a terrible racepace car but had very solid development throughout the season (despite their drivers, esp Charles being super unlucky) Mercedes had a minor overall improvement but clearly not where they expected to be. The other teams also fucked up but they gained a relatively quick understanding of their problems and managed to make pretty immediate imporvements while mercedes continues to really just... not get it. Sure, if you look at the points tally in 2023 you might get the impression mercedes was actually good, but it really doesn't tell the whole story at all.
This season is a lot smoother for the likes of Ferrari and Mclaren - turning up with a good car from the start and it really exposes where mercedes' true position on the grid is. Hell, aston could be ahead of them if Stroll wasn't so shit.
Lewis made a very sensible call, there is only so many times Toto can promise him it will get better - it just simply doesnt, its usually baby steps in terms of drivability but the pace is still extremely situational. Some tracks are good, sometimes conditions are good - but the car isnt reliable at all in terms of turning up at a track and having immediate pace. This has been an issue since 2022.
As for George, yeah its a bit of a shame but frankly no one is entitled a WDC winning car. Even driving a williams f1 car is a huge privilige that im sure many f2/indycar/formulae/literally any motorsport driver would immediately agree to if offered.