I don't buy into the notion that SMS has poor transport links (save for, perhaps, the small number of people with mobility difficulties who might need to park at it).
It is a 20 min walk from Soton Central and a 10-15 minute walk from numerous town centre car-parks. What do people want? A clear drive through to a heated, covered, concierge-serviced allocated space? A heli-pad on the roof? It's certainly much easier to get to, with more options, that many other grounds I've visited.