The thing that's really weird is that there is an underlying backend architecture behind Nintendo's stuff that seems very stable - you can still download every component of the V2.0 Wii system software that was released in November 2006 - but the user-facing stuff has all been taken down...
Nintendo treats their services like hardware, clean breaks every generation followed by rehash after rehash to get you to pay more for the same thing you’ve paid for already.
We have had friend codes since the WII! But now they are tied to the user and not the console, so I think those will remain persistent. Eshop seems to be persistent now too. I bet Online and VC will be retained in the next console as well.