From a technical perspective ETH could run BTC as an ERC20 token on the ETH blockchain, together with hundreds of other tokens....There is nothing BTC can do, that ETH cannot.
If BTC wasn't a first mover, we would not even have this discussion....
Of course not,BTC isn´t just the name,plainly the ERC20 token of ETH constitute a risk to many things mainly with the ease that can be created,anyone can create one of these and use it for many purposes too easily,from my point of view BTC is much safer than ETH,probably that is the reason many people hold the trust in BTC,barely ETH can be the biggest leading cryptocurrency surpassing BTC,there is very little chance of that happening in the near future.