why isn't russia, china, india?

Sports are artifacts of culture. Although the US does remarkably well in soccer despite soccer not being a mainstay of american culture. The question should be, how come the US does so well in soccer, despite it still being a niche sport (even then mostly for older generations).

Soccer is much more popular with gen-alpha and to an extent gen-z (thank youtube).

A lot of the top national teams have players that play in the premier league or some other european league. The American national team (last i recall, haven't kept up) typically only play in the MLS where even then the foreign players treat it as a last stop before retirement when they do have premier league experience.

iron sharpens iron, competition is what it's all about, year round. I wonder why the premier league didn't expand to the US, Canada and beyond? it has global popularity but with not logistical or technical inhibitions, it still is a europe only (keep in mind, europe is still a bunch of countries, so international) club. There aren't enough matches to make a 1-2 6-8 hour international flights a week that big of a deal (assuming a day of recovery afterwards), and/or matches can be scheduled so that they move to one side of the atlantic after a few weeks and back after a few more instead of lots of back and forth.

I would say the NFL and the NBA dominate US culture, but today, the MLS and NHL are about the same level with younger generations as soccer -- if you include all of soccer as one thing instead of just the MLS.