In my opinion , I don't think alts have chances against Bitcoins. Bitcoin will stay on top but alts might try to take its place and we really don't know what the future will bring but so far or as of the present it's a no in my opinion.
Additionally we need to be realistic about our expectation in the cryptocurrency market, that Bitcoin the most highly valued cryptocurrency has not yet fully tap the majority of the consumer market yet, and you think there is a room for one more cryptocurrency. Bitcoin as a currency needs to grow first, and what I mean about that is both consumers and sellers are accepting Bitcoin as a kind of currency. If that happen there will be a possibility that people will start to look for another cryptocurrency in the market that is suited to be an alternative to Bitcoin.
Yes, some have not even heard of bitcoin. So it is quite possible the emergence of another stronger and more popular currency.