Considering that the US has all but shut down it’s space program and there is no other country even remotely capable of accomplishing anything meaningful regarding an incoming asteroid ... mute point IMHO.
"Large asteroid heading to Earth? Pray, says NASA"
I agree there is little chance at this point of detecting and diverting a large asteroid.
However, this is at root a policy and fiscal issue, not a technological one. It is well within our tech capabilities, but we choose not to do so because we have other priorities.
Pretty short-sighted, IMO.