Over time, the gap between the wages of workers with a college degree and the wages of workers without a college degree has been increasing. Shouldn't this gap have increased the incentive for workers to earn a college degree, thereby increasing the supply of college-educated workers and reducing the size of the gap? This w

While the incentive to earn a college degree might be higher, not all people without college degrees either can afford college, or even want to go to college.

Some non-college educated people may be too poor, or might feel that they are too old for college, or may have many responsabilities and have very little time to attend classes.

Besides, technological changes and the ever increasing need for higher skills can work to increase the wage gap between college-educated people and non-college educated people even if the labor force of the first group increases.