That is an empirical question, to be decided in the future by the market.  Nevertheless it's fun (and potentially profitable) attempting to deduce the answer from first principles.

I think we'll see a diverse mix of successful approaches, because I like to hedge my ASIC loving btc/ltc with GPU/CPU based xpm/xmr/xcn.

For now let's just agree that PoS stands for Proof of Scam, along with variants Dead Piece of Shit and Proof of Suck Ass.