Sub 4m rule in 2025

Do we really need to have a sub 4m rule in 2025? This rule is holding back India in terms of car manufacturing and assembly as sub 4m cars are not normal in other parts of the world. Therefore R&D costs of new sub 4m cars can’t be recovered easily via exports. I believe this is the reason why we’re not seeing many new models compared to China or US. If India really wants to promote small cars, they can at least give similar tax treatment to sub 4m diesel cars by allowing upto 1500cc petrol engines for sub 4m cars at lower tax rate. I feel this will significantly differentiate the 3995 mm maxed out cars (a bit more fun to drive city cars) since BS6.2 rules are much more efficient than BS4 cars. Thoughts?💭