I imagine there is a bit of that. But rather than just profit, it's that there's people who have 6-7 ST and away memberships in all their families names and then use them to bring along various mates and friends or friends etc on a game by game basis. I know a few of these people. They're mot doing it for profit really. I've always got tickets from them at face value. But they just don't want to "give up" the level of membership they've managed to get to with their group of tickets. Clearly they should. But there we go. So yeah, the guy I'm thinking of ... Only 3 of the 8 tickets he has have been bought, as the actual 'legal' names on the tickets don't match the people who normally go.
TL;DR - You are correct IMO, but it's a bit more nuanced than just profit.