The Cannes jury generally does a good job of predicting what will last. Fahrenheit 9/11 was an unfortunate exception. And the Oscars used to (although I could pick a film I like more for most every year of their history). The Oscars have traditionally done a good job of educating the American public about movies.
Doesn’t matter what Cannes “predicts”. The Oscars have always been dominated by insider BS. and no the Oscars don’t educate anybody about anything.