If you include the wider urban area outside Hull (most of the suburbs are outside the city boundary, though part of the same urban area) the population is around 500,000. Statistically Hull always looks bad economically not least because what wealth there is in the area typically resides over the border in the East Riding. In terms of rail, passengers with money often board at Brough making their way there by car.
Rail service is a bit of a chicken and egg situation. Is connectivity poor because of the poor economics of the area or is the economy held back by poor connectivity? Hull has the worst TPE service of the east coast destinations, only one franchised train per day to London and no direct services beyond York/Manchester/Sheffield. Yet, has been able to support seven return trains to London per day with Hull Trains with no subsidy. Do HT demonstrate that, if the service is provided, the demand is there?