Ethereum, it its current state, isn’t very scalable. It can’t even handle a game for trading virtual cats (CryptoKitties). Ethereum was a great start, and led the way for blockchain development platforms. However, next generation platforms like Cosmos are built on all the learnings from Ethereum. They use consensus algorithms that are much faster and more energy efficient like Tendermint proof-of-stake. Cosmos also offers more flexibility for what you can do with a blockchain. For example you can add governance, and build customized incentive structures for people running nodes and validating your chain. It also supports development in Go, a language that has great tooling and is safer for programming money than Solidity.
EOS is too centralized with only 21 block producers, while the latest Cosmos testnet has over 170 validators. Tezos and Dfinity are not far enough along yet to be viable development platforms today.