If there were only 20 coins out there, the prices would probably look way more stable and we'd have no more pumps and dumps. I believe there's going to be a day when shitcoins will disappear off CMC and exchanges and only the legit and strong ones will survive. Time will tell.
Yes i absolutely agree with you only those alt's will survive that have good and working product with active development team. If you see the ico stats many of the projects are dead. And talking about limiting the coins to 20 is not practical like in every day life we see same product available from many different manufactures. So if there is demand someone will eventually supply that ..