Biggest looser here would be VI. Not only they have made packs expansive, but double data offers are also not there now and on top of that voice quality on voda network is also an issues now!!
Yes, I dont know what is the tactic here.
Many users in rural india are not tech savy when it comes to such news/updates. They may be doing recharge from shops (manually), instead of online. Poor guys are also fleeced by shop owners. So I think the old plans are retained such that even if by mistake an old recharge is done, u get the same benefits as earlier, but with lower validity. They might gradually phase out these recharges. This is just my opinion and may not necessarily be true.