That was never the case for Sancho, United simply refused to pay the price needed otherwise would've left last year. Lewa its true but they had offers of 20-30 mil for him and in the end took the loss, here the loss could be close to 100 mil, isn't not even close in terms to that of Lewa, no way they shitting 100 mil away just for another season of Haaland, as a matter of fact without Sancho they likely wouldn't even had qualified for CL, they can take the 150 mil and even make CL next season without him, or lose him next season for 70 mil and possibly even miss out on CL.
Of course fans views are important they know the Dortmund board better than we do, if most of them believe he will leave if a massive offer comes in means they are well aware how their board operate or handle it.