They need take a closer look
They need take a closer look at diesel engines. While maintenence is more, they last longer and they are more fuel efficient. I have a friend with a 1 Ton Dodge and he averaged over 20MPG on his vaction where he drove about 2k miles overall. A diesel engine, when properly maintained will last 2-3 times longer than a gasoline engine. If you flip a truck every 3-4 years, don't bother with a diesel because you won't make up for the upfront cost of one.
They also need to bring back manual transmissions. Automatics are a killer on mileage. But people are lazy and not want to learn how to drive a manual.