If Bitcoin (BTC) continues to tumble, four Ethereum (ETH) competitors, according to a renowned crypto expert, have a grim future. Altcoin Sherpa, a pseudonymous trader on Twitter, warns his 176,100 followers that smart contract-enabled blockchains Solana (SOL), Avalanche (AVAX), Polkadot (DOT), and NEAR Protocol (NEAR) price are all set to lose nearly half of their …