Are you comparing like to like? The European and Japanese test standards are quite easy and overinflate what a car can get in actual driving. The Prius gets in the 70s at least on those tests, while getting 50mpg on the EPA one. To add to the confusion, there could be a mix up between imperial and american gallons.
The Escape hybrid is also an older design that has been discontinued. Mainly because Ford knew it would garner few sales with the C-max sitting on the lot next it. SUVs are get poor fuel economy in general, and hybrid systems aren't magic. They can only do so much when driving a box.
I agree, the FEH does not get the mileage of other hybrids such as a Prius, but its also a boxy SUV with 4WD available. When compared to other hybrid SUV's of its era, the FEH achieved the best mileage of all of them.
Not comparing like for like, as they are different cars of course. I just noticed how low the MPG were for a hybrid and wondered what the deal was. I think the government has far more involvement in the marketing of cars, especialy in the US, than they let on.
I do not think any of the MPG tests are reflective of what the vehicles actually get in the "real world" of driving in city traffic, varying weather, highway driving (Interstate, Motorway, Autobahn), and drivers who really aren't trying to maximize fuel economy. In the USA, the EPA testing is designed to measure exhaust emissions, not fuel economy. And it does a poor job on that, because it doesn't measure such things as wide-open throttle acceleration up the on-ramp to a highway.
The only place hybrids actually save fuel is in city driving, where some of the energy of stopping can be recovered into batteries instead of being thrown away as heat in brakes. Batteries are not 100% efficient, nor are electric motors in either motor or generator use. Batteries and motors ARE heavy, though, and tend to make the car heavier as well as occupying space. Weight is generally seen as an enemy to fuel economy.
Stop/start engine operation has been in use probably since the electric starter made it possible, and it actually does save fuel. But remember the electricity used to operate the starter motor comes from the fuel required to generate it.
It has proven difficult to generate "real" fuel economy numbers for lots of reasons, including the obvious reason that the "real world" is not easy to duplicate in a test lab. Even Fuelly's numbers may be suspect, because only those who a) have heard of Fuelly and b) who care enough to post do so. It is a self-selected group, and as such likely biased.