Work does give you homework, it's just the self-selected kind. The people who excel and get ahead at work are the ones who recognize this and do the extra work. Whether that's educating themselves so they can make a career move, or taking on extra tasks (which often requires self-edification) to show they are worth promoting.
I think what school fails to do is teach the difference between internal motivation and external motivation. Mandated homework is external motivation for those who don't get it, and for those who do the mandate isn't necessary.