Polkadot offers better scalability than the ethereum blockchain. It offers relay chain, cross-blockchain features, forkless network, decentralized governance and all these are not available in the ethereum network. Actually, Polkadot offers all the solutions to those problems that the ethereum network can not. So many projects are using the Polkadot network. Do you think Polkadot is really Ethreum killer?
Not sure it will be a killer. Just like a another strong player on the market with its own revolution technology. It will just take it's place and own market segment. That's it.