What, though, if England can't beat Australia and are left to cope with the indignity of being the first hosts to not make the playoffs? That's a giant hole in the legacy programme right there.
But it can be filled and, arguably, the All Blacks are the team to do it. The natural consequence of failure will be for England rugby to assess the qualities of those who have succeeded.
Their shortcomings will be exaggerated by those teams who are strong where they were weak and this is where New Zealand will have gravitational pull.
Richie McCaw is the inspirational captain Robshaw aspires to be. McCaw may win universal boos and be cast as pantomime villain, but that's a role only reserved for those who are the best at what they do.
McCaw - We are in pretty good state
It's impossible to believe that if faced with a similar decision as the one Robshaw faced in the last few minutes against Wales, that McCaw would have gone down the same track. That's not to say he would have made a different decision, he would have never allowed the All Blacks to have blown such a commanding lead.
His grip on his team is too strong to allow the All Blacks to lose their shape and discipline entirely for a whole 10 minutes the way England did.
He's got too much good support around him as well - something that was noticeably missing at Twickenham. What will drop for England's management is the need to actively build leadership - it doesn't just happen because players become more experienced.
If there is one key lesson to be taken from the All Blacks at this tournament it will be the work they have done on the mental side of their game. They haven't left that part to chance and the results speak for themselves.
All Blacks: 'Kind, friendly...not nasty'
But what will be more apparent to the masses is that the All Blacks have a skill level that's higher than England's. They also have an instinctive feel for the game that the English, not just based on what we have seen so far at this tournament but for the entire professional age, don't.
If kids around the country are going to latch onto anything from this tournament once England are out, it will be the ease and comfort of the All Blacks on the ball.
Sonny Bill Williams can't help but be a focal point - the world loves his offloading. Kieran Read won't be far behind and in terms of inspiration, there won't be a halfback anywhere that excites as much as Aaron Smith.
It's not a palatable thought for the tournament organisers, but the next generation of England's players may grow up wanting to be All Blacks.
There have already been signs of that. Wembley was sold out but not filled exclusively with New Zealanders or Argentinians. The trains pulling up had their fair share of dads taking their young sons - having obviously travelled to London for the day to see the All Blacks.
New Zealand come often enough to these parts but getting tickets to Twickenham is typically beyond the reach of those who truly live the game. That game at Wembley was a chance for people across England to see the All Blacks in the flesh - and the trains leaving with dads and sons, were full of analysis that admired the patience and resilience of New Zealand to stay calm and fight their way back in. There was talk of the impact Williams made and the skills he brought; the subtlety of Conrad Smith, the work rate of Brodie Retallick and the ridiculous ball skills of Charlie Faumuina.
Right now England owns the nations' hearts. But after Saturday, it may be that the All Blacks win English minds.
- Gregor Paul in Cardiff
