That is true to some extent, but 3 situations -
You have just had someone burgle you, and the police refuse to register a FIR without a bribe immediately. What you do?
You are in the Bureaucracy and struggling to pay the bills, house installment etc.. and then you see 2 of your colleagues engaging in corruption, getting and getting away with it.what you do?
You are contesting a election for a Member of Parliament seat, your opponent is spending 20 crores putting hoarding everywhere and getting maximum exposure to a largely uninformed huge electorate. He plans to make this money back and more when he gets elected through corruption and you know that if you don't do that, you won't get elected. The pressure to do the same will be huge, won't it?
Corruption is almost like a cycle and just leaving it to the Citizens as a whole waking up one day and deciding we won't engage in corruption is not possible, because as they say power and system corrupts and you have to corrupt first on most occasions to attempt to change the system too.
There will be rotten apples everywhere but what needs to be ensured is that they don't spoil the bunch. Thus, there needs to be a institutionalized system with enough friction between all the parties(and not complicity) to ensure that that at least it is tough for this rotten apple to affect others and also to get away, if not be singled out and eradicated early. There is a will against corruption in almost all the population, but the problem is that there is not such a culture collectively.And, This culture needs to be created through checks in the system in which we live and then the will to fight can kick in(at least in terms of others) and the cycle of corruption dented to some extent with both the punisher being under pressure to punish as well as the bribe givers/takers not being benefiting.
I agree, ideally this change would be bottom up in direction, but that is not possible in the current environment we live in and nigh on impossible in a country as large and diverse as India. So it has to start at the top and then trickle down to the bottom, with many efforts to affect as much change that is possible from the bottom - upwards too.