This.
By not voting, you are showing you don't care.
By spoiling your ballot you are showing that you do care, you just don't support any of the candidates/the system.
It will never happen whilst people like you display such apathy that they can't even be bothered to show their lack of faith in the system.
Problem is spoilt ballet doesn't actually accomplish anything or more crucially have the same weight as an actual voting option. Democracy doesn't mean anything unless you can actually change it.