With Festiva's you need the dual stage thermostat to get up to proper temps in cold temps. Can't recall how it affects fuel economy. Is dual stage thermostats even a thing with new cars?
Early 1900's tech, that's why.
It has more in common with a than any modern vehicle.
Cast iron block, RWD and fuel consumption that would make a V6 powered Chrysler 300 look like a hybrid.