At the age of 33, the southern legend has already annihilated the longevity odds considering that many great All Black backs did not survive into their 30s. Indeed, some – Christian Cullen springs to mind – didn't get close.
Smith's injury/head knock problems are well documented, his form decline quite clear. Yet people keep seeing the old Ben Smith, even though he isn't there.
He has lost top end speed, no longer wins the high balls, and looked completely lost on the wing. While experience and combinations are vital in the World Cup, form is paramount on the flanks and the All Blacks have much better options than Smith.
They will probably take three dedicated wings anyway - George Bridge, Sevu Reece and Rieko Ioane – which leaves Smith as a back-up fullback option to new test No.1 Beauden Barrett.
But Smith's presence would only muddy the waters around Jordie Barrett, who is the fullback on the rise. The youngest Barrett has a few faults, but he runs brilliant lines, adds powerful goalkicking and is among the game's longest punters.
All of these attributes could be gold for the All Blacks in the intense World Cup trench warfare, and at 1.96m he's a better high ball candidate than Smith these days. For the big games, Jordie Barrett offers far more weapons and versatility from the bench than Smith does.
The best move for the All Blacks is to give Jordie Barrett confidence and opportunity in this tournament, and Smith's presence would actually detract from that.
Added to that, Bridge could cover fullback against Namibia/Canada, which would help give Beauden Barrett and/or Richie Mo'unga a rest in the pool play.
What are some options?
If Smith is deleted, Josh Ioane could be included as the third first five-eighths, and used against Namibia, and probably Canada, to give the big guns more rest.
This would remove any temptation to play Jordie Barrett at No. 10, and allow him to concentrate on fullback and providing cover in more familiar positions. This, in turn, would give better genuine security at No. 10.
If the All Blacks strike outside back problems, Smith awaits as the ideal instant replacement. This makes more sense than flying Josh Ioane to Japan at late notice.
The way it is shaping with Beauden Barrett now the test fullback, the All Blacks may go to the tournament with just one dedicated No. 10., a reflection of the muddled selection build-up and Damian McKenzie's unfortunate injury.
I certainly hope they retain Rieko Ioane. He has far too much potential to be axed from the World Cup squad. There is a slight risk given his form, but he could be a tournament star and match winner. Smith no longer has that potential.
The great All Black centre Frank Bunce talked a lot of sense last week when he promoted the value of Ngani Laumape and Braydon Ennor over veteran midfielders Ryan Crotty and Sonny Bill Williams.
The All Blacks needed players who were "champing at the bit" Bunce reckoned, and he's right.
And yet the player most obviously not vigorously champing right now is Ben Smith.
It would be a sad day, and I'm not expecting it to happen. But Smith is, in many ways, the obvious player to leave out to get a balanced World Cup back division.
