In the future some other cryptocurrency may topple Ethereum from its no.2 position, but I am sure that it is not going to be BNB or TRON. Ethereum is a smart contract platform, and its scope is very wide. On the other hand, the scope is very limited for both BNB (exchange token) and TRON (file-sharing). And at least in the case of TRON, the development activity is not moving forward.