Bitcoin is still the king of cryptocurrency and the rest are just alternative coins. All the profits of this altcoins are just the faucet for the bitcoin to go strong. I do not really know what is the scheme for bitcoin and other altcoins but i bet that these altcoins are basing bitcoin market price movement. And that is why bitcoin could never be dethrone by other crypto but altcoins could achieve what bitcoin has achieve and i am seeing ethereum has a lot of potentials but it cannot dethrone bitcoin for now.
1.
Ethereum (ETH) tried it last year around June. So called Flippening. -
FAILED2.
Bitcoin Cash (BCH)last November 2017, touted as the "real Bitcoin" -
FAILED3.
Ripple (XRP) - February or March this year, too decentralized -
FAILEDIt there's some coins that will topple bitcoin, its not yet created. Bitcoin has already gained the trust of the investors and no amount of FUD and fake news coming from different sectors or coins will simple stop Bitcoin. And I agree with @Pursuer, the only possible way to take the crown from bitcoin is that a coin that will have a real usage, but so far we haven't seen any, but shitcoins after shitcoins whose purpose is for pump-and-dump scheme.