yes of course many JWs finish college still JWs. probably most do IMO. Just because you go to college doesn't mean you automatically use your new thinking skills on JW teachings. There is still a switch in a person's brain that says "stop, I will not analyze this". And you don't need a college degree to figure out the truth about JWs, either.
I don't think a college degree changes a person's religious beliefs, makes a person more or less religious, or even increases their intelligence. It trains them how to analyze, how to write, how to work hard and how to research things, or on the flip side, how to use their sexual power or cheat to get ahead in life. Many people can learn all of that and still remain the backward people they always were.