i have a theory that all these erc20 based ICO's raise a bunch of ETH for the devs, who turn around and sell it. For this reason the market is flooded with an excess of ETH for sale, which is keeping the price down.
Hopefully as more people realize how important it is to be more selective with ICO's, the supply of ETH will dry up and therefore cause the price of ETH to rise.
I somekinda agree with you. It is not crystal clear but it feels like current icos don't wanna invest into their tokens. They are staying with ethereum to guarentee investments or basically selling out to btc.
I also lost my interest for icos, I am lot more selective now.