But you would have thought the primary operator to the North's largest airport would have more in the way of luggage racks?
Gatwick Express exists for people travelling to/from Gatwick Airport
Heathrow Express exists for people travelling to/from Heathrow
Heathrow Express exists primarily for people travelling to/from Heathrow
Stansted Express exists primarily for people travelling to/from Stansted
Transpennine Express provide hundreds of journeys (Manchester to Edinburgh, York to Leeds, Sheffield to Doncaster, Middlesbrough to Yarm etc), and travel to Manchester Airport is well under half the journeys (probably under a quarter).
Not even all journeys serve Manchester Airport. By the same logic you'd want more luggage for all Pendolinos because some of them serve Birmingham Airport.