MUFC fan - presumably you mean when FR op BLK-STN? Don't think they've ever op BLK-LGW??
LS dropped LGW-MAN for NCL-LGW and FR dropped STN-BLK - both presumably because they thought they could make money.
How does this show that A) LS are to drop NCL-LGW, and B) that LS could make more money on BLK-LGW?
If FR can't make BLK-STN pay and LS can't make MAN-LGW and NCL-LGW pay, what makes you think BLK-LGW is a winner?