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.
Actually OP is referring to possibility of polkadot overtaking Ethereum in future due to its scalability claims and other purported improved features, however I really like your points here. Ethereum's acceptability and already existing projects building on its blockchain is far ahead of any other altcoin. Ethereum developers keep coming up with innovation, hence I doubt if polkadot will be an ETH killer even in future. So many supposed "Ethereum killers" have gone extinct lol, time will tell if DOT has what it takes.