Of course any alts like ETH , XRP, or BCH could easily dethrone Bitcoin "IF" they aren't designed as an improvised version of Bitcoin which is also called cryptocurrency. These alts were created to perfect the flaws of Bitcoin, basically with the transaction fees and speed, while adding some features at the same time. But, the fact that Bitcoin is the original digital asset, that alone is enough not to argue about why Bitcoin cannot be dethroned by any altcoin in the market.
Whether you like it or not, Bitcoin is always be the face of cryptocurrency, and If someone is planning to dethrone Bitcoin, then they must create a digital asset which has unique features and usage.