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.
If you are going to speculate to the possibilities about the chance of altcoin against bitcoin first we must all consider the role of the alternative crypto-currency int the market. First of all alternative coin does not establish a rivalry between bitcoin because it is much more prefer to achieve a mutual relationship between altcoins and bitcoin on the market where it set to be an option for people to used on transaction in the mode trading or investment that may somehow make a good stability on the stock of both crypto-currencies. And we can also see that all altcoins depends on the price of bitcoin which happened to have a good relationship between the development and growth for both price, value, transaction and security.