The fact that BRS/EGGD is thriving makes many wonder if it would not be even more successful if it had become FZO/EGTG.
Almost certainly. Long haul from Lulsgate isn't sustainable with the payload restrictions or fuel stops that hindered the previous attempts. With Filton's long runway, the EWR route and TOM's bucket and spade services would've almost certainly survived. Far superior ground transport connections would've only bolstered this further. It's a shame, but that's UK politics.