I was lower executive level at a major car company for 10 years.
Believe me, model line-up decisions are not made lightly. And Toyota is not stupid, probably the most respected auto manufacturer leadership in the world.
What the consumer wants (or is perceived to want) is one important consideration. But meeting government mileage standards is critical. For example if you want to sell more full size SUV's (where the profits are), you need to sell more high mileage cars.
There are also supplier issue. For example a supplier may only invest the capital to make new production facilities if they are guaranteed certain volumes.
It is a complicated decision trying to balance customer wants, government mandates, and suppier requirements.
It's not easy.