I don't buy the theory that Spicejet is filling its seats simply because of its scheduled timings. If that were the case, Jet/Sahara combo would tweak their schedules to increase loads. I think it has to do with pricing and routes chosen by Spice.
Jet being a public company has to focus on profitability. It is not clear to me that Spicejet is profitable - maybe they are foregoing profits for loadfactors. If so, it would be a bid error. I don't understand their positioning or strategy. They seem to be doing OK for now.
On the other had it took a while before ATA cut down drastically, Indepenance liquidated or Hooters Air shut down. We just have to watch I guess.
One advantage that LCCs have is that on some domestic routes in India, demand growth is 50%+ so everyone could do well. Consolidation may still be some years away.