I think BTC will remain the gorilla, though there'll be a few monkeys also, and on the periphery there could be any number of specialist coins/tokens.
The reason I say BTC will prevail in the crypto world is that if anyone makes a novel useful feature, then other coins can incorporate that. Eg. Litecoin is a good coin with a good crowd and I think it will do well, but it's sort of a testnet for Bitcoin (SegWit, Lightning etc) - it does score points for filling that area though, and will likely be rewarded in leaps each time it does that. LTC is nimble enough to incorporate this stuff first, but BTC is foundational and nobody wants to mess with it and be flighty. Ethereum is a good example of how not to do it. Multiple forks and hacks on the tokens offspring (not just exchange hacks that anybody using them is exposed to), but the technology itself not being thought out properly before making the leap. But that's what 'teenagers' do the world over.