I don't have enough experience about India to comment on that but in the US the amount of money it takes to influence a politician is quite low.
What we actually see is a lot of stasis, refusal to compromise, and politicians locked in with their party, which suggests it is pretty hard to influence politicians.
Where money is effective is using it to get politicians who agree with your view elected.
The only reason all those “issues” are issues is because they’re intended to distract the public from the actual stuff politicians are being bought for. Transferring wealth to their buyers.
80% of the politicians on both sides of the spectrum have the same beliefs about all those issues.
India is ridiculously expensive - bribes often amount to 50 lakh rupees to 1 crore + rupees, which amounts to roughly $50k-100k per politician. Not to mention bribery at the lower rungs of the ladder where everyone from the politician's toilet janitor all the way to the politician's chief of staff will demand their pound of flesh, usually in the tune of tens of lakhs of rupees (~$10k).
Why would you agree to stick your neck out for something illegal on the cheap when you can wring the ordinary people to do your job?
All this is based on second hand information so please correct me where I am wrong. Also probably things are different in different parts of the country?
On the other hand, I was a member of the Treasury group and the Leaders group of the Tory party until recently, with just a "paltry" donation of £50k, which got me the ear of a sitting PM and regular meetings with the Chancellor. Good luck trying to get that kind of access in India or the US with the PM.
The cheaper bribes were a tangent, but just to show that doing business in India is actually more expensive than in the UK (where there are no such bribes).