there's a couple reasons why it works like that.
the older mercedes and even BMW had seats that operated in the same manner, as well as saab (as has been noted) and volvo.
with the little wheel, it accommodates for "infinite" adjustment. where as with a lever, you've got "steps."
the europeans have a different design philosophy that other car makers.
just like it took them decades to engineer usable cup holders into their cars, the issue of reclining seats is not a big deal for them.
you see, to them, it doesn't make sense to sip your grande latte mochachino with a shot of espresso while driving your car. in fact, in many countries, drinking and/or eating while driving is illegal. and as a result, they found zero need for having cup holders to accommodate such practices. they expected the driver of the car to do just that.... drive.
the seat issue is quite similar.
things are closer to each other in europe, and the average european doesn't exactly go on very long treks in his car. as a result, seats that quickly and easily reclined to the horizontal position were never really developed.
it was more useful to them to create a seat that had "infinite" adjustment by turning a small knob in smaller increments until you found the position that was "just right" for you.
that's what they needed, it's what they liked, it's what they used, and it's what they sent out to the rest of the world because it was good enough for them.
just like when they didn't put cup holders in their cars.
ps- there was an excellent show on Discovery about this very topic... well, cars and their designs in general, but it went into the seating, the cup holders, and other things pretty specifically.
