Discounts are up to me, not enforced by US billionaire disruptors.
I guess they are in a way. If you were opposed to Uber giving 20% discount off every fare you could delete the app. Alas, neither the vast majority of drivers nor their unions will support that course of action. The fact that the discounts are putting millions of euros in drivers pockets combined with the fact that drivers don't think beyond the next €1,000 dictates that they will trouser whatever coin is on offer.
In a no pain no gain sort of way I'm leaning towards concluding that DoT/NTA banning below cost selling would be a positive step. Yes, in the short term, it would take money out of drivers pockets but it would also present opportunities for drivers to box off the best of the work be that systematically like the Indians or individually.