Google isn't making arbitrary decisions here - it's reflecting social norms. Americans aren't big on walking. I've seen pictures of beautiful leafy suburbs that don't even have sidewalks.
Google has giant offices in NYC. Like, you'd think this would have come up.
This is overstated. At least as of 2017, Americans walked about 93% as much as people in France, for example, and a little more than people in Portugal or Greece.
https://www.statista.com/statistics/747380/daily-step-averag...