Though I agree very much with what you are saying, there are two big factors that influence that:
1) I dont agree with people saying we cant sell him on, he is probably one of if not the most valuable expendable players we have
2) As things stand Garnacho and Rashford are way ahead of him on the left and he hasnt been effective on the right...and we have Antony, Pellestri and the returnign Amad there.
Elanga is very much surplus to requirements in my opinion, but what does he bring in £10-20m maybe as a guess, Sancho I still think is somewhere around a £50m player...if you count the lazy but obvious likes of Newcastle as an example.
I could name 12+ players need to go above Sancho, so I agree, but in a summer where personally I believe we need to make six signings....and I dont buy into the vast vast majority of free transfers people keep mentioning, just speculating, but selling Sancho pretty much makes a negative spend out of Kim Man-Jae relase clause and Varane/Jae and Garnacho/Rashford looks to be more valuable than Lindlof as the option and Sancho as a third winger. We cant make all six signings without good funds incoming, which can be achieved with the number of players should be outgoing anyway, SAncho sale if there is interest, makes it far easier though, thats why it shoul dbe a consideration, lets be honest he has done little more than another fantastic winger was here in Sanchez in a similar timeframe