Their incompetence, your money
Hat tip to nclean, who adds re the Australian car industry:
"Ford and (GM-)Holden make big ugly cars that almost no-one buys for themselves. The people that buy Falcons and Commodores pay for them with other people's money - that is, about 90% of sales are to fleets. It's not surprising that when people can adopt an attitude of "I don’t have to pay for fuel, because I've got Salary Packaging," that they prefer larger vehicles. Everyone else avoids them."