The main reason for India not able to produce good genuine fast bowlers is because of these following men Sachin, Dravid, Ganguly, Laxman, Sehwag.
They have been the role model for many people of this generation. People who were born in the early 1990s and onwards know these men as the definition of cricket. Every other kid in every other colony in India holds the bat first and wants to become Sachin/Dravid. Undoubtedly they are the role model for thousands of kids. Not many people born in the same time period admire Kapil Dev as much they admire Sachin/Dravid purely because they haven't seen Kapil Dev bowl.
Now consider Pakistan, I am pretty much sure the kids born in the same time period over there try to imitate Wasim Akram, Waqar Younis and Shoaib Akhtar mostly. Again they might not have seen Imran Khan play either.
In India there is a lot of fight to be a better batsman. As there's more competition in batting there is more development and hard work involved.
Role models are very important in life. When you are in a nation that has mostly bastmen as the role models then it is quite improbable to have the same passion for bowling as you grow up. At the same time I am not saying we don't have people who are passionate about fast bowling but it's just that it somehow gets subsided.
Another main reason is that they play in flat pitches batting paradise and all and whenever there is a fast bowler in the picture he somehow loses his pace and is being told by the coaching staff to concentrate on line and length and compromise the pace.
I would like to highlight some bowlers
ISHANT SHARMA:-
He was the considered the next big thing in Indian Cricket after the 2007 Aus series down under but after coming back home he was ruthlessly taken for runs in the first IPL .
And after that his pace reduced a lot...He lacked the pace ,the aggression and the fitness a fast bowler had.
IRFAN PATHAN:-
Yeah he is the one who took the hatrik in Pak but after arrival of Greg Chappel he lost his swing .He was converted into a batsman and rest is history.
SREESANTH:-
One of the most talented bowler India ever produced but we all know what happened with him...slapgate,fixing etc.. He was always in news for the wrong reasons.
RP SINGH:- He too was a good bowler and made his mark in the team in the 2007 T20 world cup but failed to continue his form and fitness.
VARUN ARON:- Another bowler who bowls fast mean really fast but with no real control on line and length.
UMESH YADAV:- He too is similar like Varun Aron but leaks too many runs. As he did in the recent series against South Africa.
BUVANESHWAR KUMAR:- He used to be a good swing bowler but in the quest of increasing his pace he has forgotten his strength of swinging the new bowl which has made him unaffective bowler with the new bowl.
MOHAMMAD SHAMI:- The only Indian bowler who has shown glimpses of being one of the best fast bowler for India with his recent form but he too is unable of maintaining his fitness.
On the other hand MOHIT SHARMA is more like a MUNAF PATEL type of bowler who can bowl good tight overs in the middle. He is more a stump to stump type of bowler and not a new ball bowler.
India has one of the most reputed pace foundation in the world but the pitches in India don t help there cause.
Another reason which may be irrelevant is that India didn t have a "Sachin " kinda God like figure in the bowling department...because many cricketer like Kohli wanted to be like Sachin not a "Javagal Srinath " or a "Venketesh Prasad" .