That's an interesting question, but it skips some steps. The reason is that these are all post-war constructions. London and Paris (I don't know Seoul) alread

That's an interesting question, but it skips some steps. The reason is that these are all post-war constructions. London and Paris (I don't know Seoul) already had dense, walkable cores that predate not just the modern highway, but even the automobile. Inner London was 5 million people in 1911, and the rise of the car drove that population down! And things didn't really get going until the highway boom. The interstate system (and similar projects in Canada) didn't start until the 50s, and didn't finish until the 80s. So this whole project is fairly recent. Highways enabled a whole new kind of development - the suburban project. And now the boom is over, and it's time for the hangover. And you'll note that it hasn't been all at the same time. LA famously hit these limits in the 80s. While Atlanta only hit them in the last couple of decades. What you're seeing is the end of a long process.