According to writer Tamara Erickson in this piece at Harvard Business Online, they may decline in value. Why?
as competition for college-educated employees increases, companies will become more and more motivated to use those without college degrees effectively in the workforce, in jobs that today would routinely require a diploma-in-hand as the price of admission. They will come to screen candidates in different ways, searching, perhaps, for the Simon Cowells among them: those who are bright, motivated, and will make them money.
Another reason: “a perception that at least parts of today’s college education are actually not particularly relevant may pervade more and more young people’s (and older employers’) consciousness.”