I suspect that O rolling stock and locomotive COULD return to the US, but we’d pay a lot more.
Once, after buying a British modeling magazine to steal ideas, I went and perused the ads for O scale locos, and saw a listing for a loco made by a certain well-known manufacturer who used to make stuff for Con Cor back in the day.
NOT CHEAP. You could get two or possibly 3 MTH locos for the price. But I think they are made in Europe, not China.