In a world where people occasionally steal $100m, that implies a maximum sentence of ~1 year for stealing $1m.
It would be nice from the perspective of reducing the incomprehensibility from white collar crimes that net hundreds of millions of dollars though I'd be concerned about false charges... well, I'm generally concerned about false charges so we just need to fix our justice system, then such a scaling might make good sense.
Just to briefly note, these crimes aren't victimless, people who pull these sorts of stunts are taking money out of someone's pocket, usually fraudulent stock maneuvers will end up negatively impacting retirement mutual funds, sometimes other white-collar crimes may be more impactful, prematurely issuing foreclosures deprives people of their household. In the former case the damage is spread around and less horrific feeling, but both are terrible.