Do Countries Have a "House" Sound

If Japanese and English societies are so different from the US in ways that cause them to make audio equipment that's better suited for their own cultures, then why do they sell more products over here, than they do in their own countries?

I'm not saying that there is any 'lockstep' correlation between those factors and the gear sold, per se. Just that that those factors have tended to be in play, over at least the last 50 years or so. The international markets, too, have proliferated between countries/cultures over that time. We sell more to them, they sell more to us, in all things audio. Are they tweaking their sound to fare better in our markets, or is everybody's tastes now gradually changing and becoming more varied within borders due to a 'cross pollination' effect over the last few decades, as well? I mean the cross pollination effect from this social-media-driven, hi-tech, hi-hype, online world we're in. Since WWII, we've given the Japanese Elvis and jazz (jazz being something these days they seem to appreciate as a society more than we do), the Brits have given us the rock "Invasion", as we have given them the Hollywood version of the wild west, among other things. How much these kinds of things are working to break down those factors I mentioned above I can't really say. About all I can fathom from it is that the magazines I read on this topic back in the day did make mention of such things as different sounds from the East or from Britain, for example, but that it seems to go all but unobserved today.

Might be that the US population is 3 to 5 times as large.

Yes, I did neglect to mention that.

It may be odd, but few audiophiles I think would question the audible differences between countries/cultures when it comes to tubes.

Could be.