My experience/understanding has been different so far. In this forum itself, several successful cases are documented, even at first attempt. I remember an extreme one to be 17 years!!! And plenty other examples of 5 yrs or more. I personally know 3 cases with more than 3 yrs gap, all nailed in first attempt.As i said majority of cases with gap of more than 2 years even with a valid reason don't get visa. Although sometimes cases with 3 years are still excepted by the embassy. I am saying this as i have been working in this area since 5 years.
I honestly believe it is lack of documentation than study gap itself causing the damage. That's just my view though...