Ethereum’s dominance in DeFi faces potential challenges from emerging public blockchains like Solana, Avalanche, and Polkadot. These rivals offer faster transaction speeds, lower fees, and scalable architectures, addressing Ethereum’s high gas costs and congestion issues. Solana’s high throughput and Avalanche’s subnet flexibility attract developers, while Polkadot’s interoperability could fragment DeFi liquidity. Ethereum counters with its established ecosystem, robust security, and ongoing upgrades like sharding. However, if these competitors gain significant developer mindshare and user adoption, Ethereum’s monopoly could weaken, though its first-mover advantage and network effects remain formidable barriers for now.