Ambitious or highly dedicated people will always work more than that, and that's a good thing. What they should have is a lot more freedom in how they spend that time-- working two jobs, one job and school, side projects.
The problem is this bullshit conformist fiction in which everyone has to pretend to be ambitious (but only internally) and dedicated (despite mediocre social status and compensation, that fail to justify such dedication). I don't think that such a problem can be legislated away. The best that the law/government can do is to break up the collusions (e.g. among VCs) that keep talent trading at such a dog-low rate against property.
The other problem, and one of the main reasons why the 40-60 hour anachronism lives on, is that companies aren't really buying (as they see it) 40 hours of time. They're also buying (in their entitled view of the world) single-minded loyalty. That's why they demand hours at such a level that a person can't possibly hold two jobs, even if she is easily capable of the work. The goal isn't just to get some quantity of the person's work, but to take that person off the market so no one else can hire her.