[A2A] The primary reason that it has become a must have is because the quality of teachers in schools is really poor. Coachings have better teachers which makes the primary difference. Objective exams don't help the cause either. Your time management has a significant influence on your performance in such exams.
So, the solution to reduce the influence of coachings:
- Improve the quality of education in schools.
- Bring back the subjective exam in JEE.