A question back to OP, what do you think will be the use case of altcoins if bitcoin never existed in the first place? Top altoins like ripple have better chance of getting implemented for real use case as means of payment around the world because its centralized
The possible thing to happen there will be no a blockchain protocol as bitcoin is the first coin who has bought it for us. Remember the creation of smartcontract was also coming from the further development of the bitcoin source code and that means bitcoin blockchain as the basic reference to buy the current existing protocol in the market