They're a lot, but you get what you pay for. The Panasonic drive-through-the-gears system is one of the best around, especially for hilly terrain, and has been in use for some time - this is the second version now. After you try riding one with the Panasonic system you won't want to go back to a traditional e-bike with a throttle and hub motor.
Because it drives through the gears, you *have* to pedal it, and that's how it gets good range. We're getting about 32-33 miles on high power mode, including some hills. Standard power should get this above 40 miles, and low power even more. Plus, when the battery runs out it's a bike that rolls very easily anyway, unlike some other e-bikes which are a pig to pedal when the battery dies.
In addition to that the rest of the bike is top-notch, with the best shimano 8-speed hub gears, deore XT brakes and front hub, Busch & Muller lights wired in to the main battery, solid rear rack, lightweight stand, strong powder-coated frame, lightweight rims, puncture-resistant tyres.... you get the idea? It's quite a bit lighter than many other e-bikes.
Basically, if it was a normal bike it would probably be £500+ (at a guess), the battery adds something like £3-400, and the motor system adds some more. Plus, it's made in Germany (rather than China), and I expect the volumes are still lower than a normal bike.
But you're right, it's a lot of money, so it really does have to be seen as a car replacement, not just something to help when you're too lazy to pedal!
We've still got the car, but are working on replacing many car journeys with the bikes. Tracy would not have attempted the trip to work I mentioned above on a normal bike, as it would have taken too long to be practical and there's no showers at the other end. With the e-bike you still put some effort in, but get there much quicker and don't get hot and sweaty.