If Trump does win in 2020, will learning Russian be mandatory in public school?

Nu, eto ne meshalo by izuchat’ russkiy yazyk. Dazhe radi togo, chtoby eto byl prekrasnyy yazyk!

O blin, teper’ ya otdal, chto ya russkiy bot…

Probably not.

But even if true, a room in the best 5 Star hotel in Moscow is $70–80 USD

Not a bad deal. Moscow is sort of weird, but no more so than New Orleans.

Perhaps English will start being mandatory.

Perhaps
But don’t count on it