This naturally makes sense, PoW alts can't properly secure themselves anymore because of either Scrypt Asics, botnets, or simply not having the hashing power of Bitcoin. I expect many PoW alts to start failing and continue decreasing in market share because of this. Look how litecoin just recently lost number 2 in market cap -- http://coinmarketcap.com/

The exception to this are coins that depend upon the security of bitcoin blockchain like coloredcoins , counter-party, mastercoin, and namecoin.