Promise of what? I think the major change with millennials and gen z is that we see through the dogmatism that is corporate culture. Even if the promise was that of the “American dream” 50 years ago it’s quite clearly not worth it to sacrifice your youth and 1/3 of your life (another third being sleep) to afford to sit around in a house and squeeze in stagnant social obligations for the rest of your life.
Life is what you make of it, and familial loyalty to a company that doesn’t care about me just doesn’t cut it.