The new ICOs are not on the decline. Cardano fluctuates even more in price than the etherium, so I think that the etherium is better suited to save your money. In addition, I'm not sure if the Cardano team will be able to surpass the capitalization twice from the one that is now. I'm not talking about ranking in the top three of the Crypto-currency.
Don't look too much at market cap, everyone knows it's a misleading indicator, unless you haven't been paying attention. In the end, the only thing that matters is the code and the tech, not the price or the market cap.
Otherwise EOS would be the champions of the world by buying their own coins using their millions of ETH... Did you see the insane and unnatural volume since the weird and parabolic price spike?
my advice do not sell your ethereum, because ethereum is believed to be number 1 later,
and will replace bitcoin in the future, surely you will lose.