Reason: the DEA will lose power with less regulated substances. The only goal of some bureaucrats is to collect power, not only because it allows to have a better pay, but because mediocre people are inherently attracted to power itself.
Therefore in a more liberal climate I would expect to see progressive access laws continue to be available to non-impoverished white populations, with the federal schedule remaining intact. Now, I simply expect a return to the old strategies for corralling free labor.