I agree with the second paragraph wich is why I don't agree with the first one. And occupier are in a better position to do what you talk about in the upper paragraph but even more vitally they would know that its needed and want to do it. But the people of India are proud of their culture and nation, so the idea that they would turn their back on their heritage and suddenly copy western nations is quite frankly absurd. If that was possible then they would have done that by now.
A.) Occupiers don't have to do it, or anything for that matter. They can get 40% of the manpower from India solely for occupying the subcontinent for a few years.
B.) All evidence suggests no occupier would want to put in the work to radically improve agricultural infrastructure in occupied lands. Indeed, the British occupation made a point of reducing agricultural infrastructure when they took over because they could turn a quick profit by emptying grain reserves and breaking down inter-community support networks and instead taking any excess production for their own enrichment. Occupiers tend to be more interested in what they can take out than what they can put in, as well as more interested in taking what they can now than having more to take later. If anyone would have the will to industrialize agriculture in India, it would be an Indian government, not an outside military occupation. And if you must insist that they would need outside assistance, well it sure is a good thing India's independence routes involve asking more industrialized nations for help.
C.) You're still framing your responses as if I'm saying the modifier should be completely removable or that any reduction should be done in one shot. I suggested a series of several decisions and/or focuses that would use significant amounts of CIC time, PP, and probably also directly consume certain items from the stockpile like MOT and MECH, and each level would probably require a certain number of factories, each greater than the one before. If you really like, it can also have a stability penalty.