I didn't say anything about cars and as Hamuko has pointed out, it predates cars. Wikipedia supports this claim, though doesn't cite it.

Interesting! That’s a bit surprising to me. In Japan they have the yellow tiles with bumps near the center of most city sidewalks that I always assumed was a kind of lane system. If it’s not to create lanes, what are those tiles for?

They are tactile paving for blind and partially sighted people.

https://en.m.wikipedia.org/wiki/Tactile_paving

Lanes for the blind.

This. As a driver and a long-term resident in Tokyo, I try to stay to the left as a pedestrian, but I estimate the odds of the other party doing the same are 50/50.

Yeah, and you also see people being paid to direct the flow of human traffic at the super busy stations.

They come in contact with it though, from those driving around them. Then there are other customs, like standing on the left side of escalators (except for Osaka, where it used to be the right side, but now it's mostly the side the line is already on). From my personal experience people in the major cities seem to prefer dodging to the left, all things being equal.