Lifthrasil: Well, here in Germany you hardly ever see indicator lights flashing, since almost no one uses them. And the more expensive the car is, the less likely it is that the driver uses the indicator.
So that's your explanation right there: old cars (probably bought used) are comparatively cheap. So people use the indicator. New, modern cars of the type with lots of electronics and fancy designs are expensive. So the drivers tend to feel entitled to behave like assholes. And not using the indicator (except for tailgating) is a requirement for being a traffic-asshole.
My wife bridges the gap by hitting the indicator after she's turned the wheel, often after the tires have crossed the line. Makes me nuts. It's the difference between asking for permission to move over, and saying "Get out de way! I'ma comin'!"
Doesn't help that I'm not at all a good passenger, because I absolutely KNOW that nobody drives as well as I do. ; ) But seriously, my brother tailgates badly and shifts really late (for no good reason), mom brakes late - even in winter, and the wife signals late and has these other habits that make me want to open her door and shove her out so I can slide over and drive the right way.