after etherium all coins will collapse. no coin can absorb so much mining power. it will all depend on how many miners will be transferred to another currency. ethereum classic will absorb most hashrate as it is a similar currency and has quite good prospects. unique solution buy the coin you are mining, only this way the coins will keep their value.
It can be ethereum classic after the mining is over for ethereum , i guess the most dosnt know that ethereum classic was the main ethereum chain but thats another story.
Oh wait you have written
etherium but i think you mean ethereum right ?
Why should there collapse all coins , that makes no sense , if they switching all the mining power to another coin the difficulty goes up and you have the same as it was with ETH.
yes ethereum I meant. The difficulty will increase and the rewards will decrease but the price of the coins however I do not see it increasing to offset the profitability.