The team, team principal, and investors definitely care a lot about getting WDC in addition to WCC. It's arguably a more glamorous prize than WCC and it's another trophy in the cabinet, and a huge amount of extra press. So I think they definitely do care about winning WDC too.
Maybe. Or maybe you agree before the last race as a team that if there's a chance for a WDC, you take it. 10 years from now people will remember the name on the trophy much more than they'll remember there was a position swap to allow it.
I have to strongly disagree here. Lando is enormously popular among McLaren fans, and has been for ages. There was an entire stand for his fans at Silverstone, he has his own Monster flavour, there's always hordes of Lando fans at the driver talks. I'm not saying nobody likes Oscar but I think Lando is by far the more popular driver among McLaren fans.
I don't think it's that obvious that the largest group of people would prefer letting a WDC slip through their fingers, when they had it in their power to make it happen. I think very many people would much more strongly prefer to have the WDC than to not have it.