Altcoin's future is shining especially after the last increasing of BTC, so many new investors will start buying and holding altcoins since they have lower prices. But there are always few number of altcoins which have real potential, because the other coins haven't value almost.
Yes, and even when bitcoin is worth the price on the spot, there is a huge transfusion into alternative crypto-currencies. So in 2018 everything should be cool in this regard, I think now you can worry only about the correction that is now going on.