It's not like things were too different before. Mukesh Ambani supposedly referred to the INC as Apni Dukaan. Both the Congress and BJP are more than happy to appease Motabhai.
Source: https://www.outlookindia.com/magazine/story/mukesh-said-haan...
Remember Auditor General of India, CBI(FBI equivalent) discovered and booked Congress-alliance party members for scam while they were ruling? Now, CBI has become a laughing stock is being used as lap dogs for ruling party to get parties into alliance with them.
The CAG is a very different body - it is much more independent of government, and did raise issues around 2G spectrum allocation and many other areas during Congress time. I mean, the UPA had a minister running an entire TV station out of BSNL lines running to his home, so really it was pretty blatant and hard not to catch.
We should not confuse this type of corruption with doing favors to business which does not show up in government books, and is not easy for CAG to catch.
e.g. Roads cannot be dug up by BSNL for repairing their telephone lines, where as Reliance can. If they indeed proceed to dig up the road, they are threatened with a police case. In several cities, only Reliance have permission to dig the roads for new telephone/broadband lines.
In HAL, future Aircraft/Helicopter productions were halted after the Rafael deal was signed up with Jr. Ambani's Reliance. But when the whistleblower letter from PMO hit the roof, supreme court was involved, some HAL old projects were given permission to continue to not raise suspicion. But still, many in HAL beleive it's done for and only companies in nexus with BJP with no prior experience will manufacture military Aircraft in the future(This was before the China fiasco).
The Rafale deal is not even about manufacturing fighter jets. Not sure from where such anecdotes come from.