Discusion essay(300words)

Many college students have a doubt about staying  in the college. Because the cost of college education is creeping up and many financially successful business people do not have college education.(successful stories of college drop outs such as Bill Gates,Steve Jobs, Larry Ellison, Michael Dell etc.)
Equally  it's true that many successful people have a solid college education background such as Warren buffett.
Do you think a college education is still a good investment  for future financial payoffs?
 
1) what's the opportunity cost of typical college education? what's your opportunity cost?
2) Compare earning potentials between high school and college graduates through life time active career.
3) what's your opinion about staying or dropping out from the college?  

4) Since the future will be highly technology oriented, will the  higher education be very necessary ? Because the robot with artificial intelligence can replace many jobs of human labor in the future.