I think carom is still dominant in most South American countries, Korea, Vietnam, and Turkey. I'm not sure what's happening in the rest of Europe.
At one time carom was more popular in the US than pool, at least in certain areas. Willie Hoppe got mentioned in a 1930s movie when one character quizzed another on which form of carom Hoppe had his championships in (balkline, answered correctly, which was pretty good for a girl).
Today in the US, I'd say that carom is primarily a game for the immigrants from South and Central America, Korea, Vietnam, and Mexico. Recently a Turkish guy reopened a room with five tables near me. I've heard of immigrant-run rooms with 10 to 15 10-foot heated tables. If you look at the US National Champions in the past 20 years, few native-born Americans appear:
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