Most of the cryptocurrency users haven't even heard about Polkadot. And the OP is claiming that it is going to kill Ethereum. The biggest strength for Ethereum is not its technology. On the other hand, its biggest plus point is its acceptability. Even now, more than 90% of the new tokens are being created in the ERC-20 platform. None of the other platforms can even come close.
even I, just realized that there is a coin called polka dots. well, I don't know what business this coin is in, but its position is currently rank 9 in CMC. Even so, I think there is still a long way to go for this coin to replace Ethereum's position. in fact, for coins that are close to ethereum, it is still quite difficult to replace ethereum's current position. Are you sure that the function of polka-dots can exceed people's needs for ethereum ? Personally, I don't think polkadot will replace ethereum for now.