i guess the process is pretty predictable . heres what i think on the discussion happening here:
Blame yourself : i guess alot of ppl are blaming the coaching classes for their training on GD/PI. but then nobody has the guts to miss such trainings! Even i had attended the IMS achievers session and i can tell you that there were no spoon fed answers. they were just urging ppl to think about what they want. i dont know about other coaching classes but i can say that you cannot blame them either. it would be majorly stupid of you to listen to someone and say something that you dont really believe in .
Here the major driving factor is not aspirations but insecurity. I have seen ppl so insecure that i could hardly believe it that they ppl have got calls and are supposedly the best and brightest in the country. And when insecurity takes over you are likely to do things you wouldnt have otherwise done. how many of us would have really gone for mgmt as a career option if it wasnt that great paying?
Profile Matters : BAs, Bcoms , BScs and other lesser mortals have virutally no chance of making it to the IIMs. when the interviewers read on your profile that you are a non engineer, they expect something spectacular and if they dont get it you are out. IITians , big brand names matter alot. I guess they choose to ignore the fact that ppl join IT companies based on which one gives the maximum bench time to prepare for CAT

the GD/PI is just a formality. even if some stud IITians keeps quiet during the GD PI , still hes bound to get in.
its about Acads not management: if you have been a topper all your life , you will do well as a manager , thats the mantra. no wonder that iim a from 1961 till date has only a few "illustrious" alumni , many of which you wont even have heard of .
http://www.iimahd.ernet.in/recruitment/recruitment_why_alumni.htmno wonder is your managerial aptitude tested and all hte business mags read are just useful for GK. which was the first indian company to be listed on nyse? if you say infosys they will give you taht dirty look. if you say icici bank , they will move on to the next q. thats it! so its not about developing managerial skills in ppl who have them , but to teach them by brute force to the so called achievers.
everybody looks the same : unfortunately theres no room for creativity. if sidin the author or gaurav the musician would have chosen their current professions BEFORE joining IIMA , they would have never made it to IIMs!! thats coz everybody should look the same!
Placements matter : during the interview , they also see how difficult it is for them to place you. so if you are an IITian with killer workex , then the choice becomes really easy. if you are a fresh BA , again the choice to kick you out becomes really easy!

besides there is unhealthy competition between the top IIMs on who gets the highest salary! so every iim is looking for that loser, that over qualified geek who will get the highest salary and put their names on front page. what happens to these ppl after two years can be anybodys guess! :|
i think slowly but surely we all are caving in to the hypocrisy. if somebody asks you your hobby instead of giving them your real hobby , you will give them then one which has "added value" to your personality , has played a pivotal role in character building and blah blah. but not to worry my friends , in a few years time , we all will be transformed. we wont have any reservations in bluffing or blowing our own trumpets .
the purpose of this post is not to discredit ppl who have got admissions into the IIMs but to let the aspirants know that such things might exist. its always better to have a few good backup options ready!
Best of luck everybody!