Some will survive and when they do, they'll be bigger then ever. All the other coins will be traded in the LTC or doge markets only or be forgotten after a week.
You need a strong dedicated coin dev team to survive.
At least 20 alts will grow bigger long-term, imo.
The future is almost without limits.

Do you think our Average Joe, house wives will use 20+ crypto coins on their phone?
Do you think Overstock will add more 20+ coins along side with Bitcoin ?
Hell no. Only one cryptocurrency will go mainstream and receive mass adoption. All altcoins will die because they have virtually no consumer, they have only hoarders and miners.