You nailed it right there. The people who haven't got "all that money squared away" won't even entertain the idea of PvP, without counting those who might have the money but simply don't want to PvP in Elite Dangerous.Nobody is going to go PVP without knowing they might need a rebuy and will thus have all that squared away and can cover the cost.
Reading this thread, there are a lot of reasons why PvP is unpopular.