QC: Nintendo does have an account system. It comes from their website, you register the system and the titles through there. That's your method of rescuing games from being lost. Plus, you're assuming console death is going to kill the memory as well.
Of course they have an account system
technically, can you buy a new Wii, Wii U or 3DS, simply log in with your acount information and re-download all the games you have purchased on one system? What good is an account system if it just exists on paper?
If your Nintendo breaks you might be able to contact customer support to transfer your purchases over, but first of all there is no reason it should be that complicated, second I don't think that service is part of the TOS, so it's imply based on Nintendo's good will.