Go back 30–40 years and the proposition of an American learning Japanese probably sounds a lot less ridiculous.
Learning a new language as an adult is incredibly difficult. I have learned Spanish to a basic conversational level and it has been a massive struggle for me.
My Swiss and German friends seem to pick up new languages super easily though. Likely this is because they learned a second, third, or even fourth language as children.
So, not impossible but it is good to acknowledged that this isn’t an easy thing to do and likely would be a generational shift kind of thing.