I guess your Q relates to a student who has received career counseling and another who has received NO counseling. Well, the difference can be VERY big, especially if one has not been able to identify what career would be the most suitable career fit for you.
Let me elaborate this point. A good Career Counseling program starts with a comprehensive Aptitude-cum-Interest Identification Test ( almost 2 hrs-45mts) followed by a one-to-one counseling session with an experienced counselor. This process helps to evaluate your strengths and weaknesses and consequently evaluate your TRUE POTENTIAL for a particular career choice. The second part of the test, identifies your interests, what kind of job you would LOVE to undertake and which shall make you not only successful, but also HAPPY. Once these details are available, the one-to-one session will help to identify the MOST SUITABLE CAREER FIT for YOU. And then help you to make a PLAN on how to achieve your goal.
Now, compare this with someone who has had NO such guidance and moves forward in life, its is like someone playing football in a field and does not know where the goal is !