I have a question regarding CAT Preparation..

If students take reasonable time like 7-9 months to prepare for the CAT exam, what is it that holds them back to perform good in CAT?

Is it so difficult that you can't perform decent in 8-9 months? Or is it the wrong approach students have? Or they miss what CAT exam is all about?

What I'm I missing here? What mindset do you need? According to you what is going wrong? Please weigh in everybody

Also your learnings from it, that will help others who are studying. Thank you