We crave “sweet” so that we would eat fall ripening fruit quickly.

We crave “salty” because inland living humans became short of sodium.

Today fruit is available year round and
miners can turn out vast amounts of cheap salt from the beds underground where ancient seas dried up as continent movement “squeezed shut” bodies of sea water that sunlight then evaporated.

Today, humans should realize sweet and salty are no longer good instincts.