Ultimately, it means the trajectory towards the 2023 Rugby World Cup changes.
Scraping a series win would have masked the issues, but the performances in Dunedin and Wellington exposed them to the world and underlined the need for change.
If that means the New Zealand side arrives in France in 14 months as a more competitive, powerful unit, then the last few weeks will be a historical footnote.
That was the key point made by Irish captain Johnny Sexton immediately after the final whistle at Sky Stadium.
"It means a lot now," he told Sky TV. "I know in a year's time, when the World Cup starts it won't mean anything, as we've learned before."
Sexton was likely referring to the last World Cup cycle, where they seemed to peak in 2018 and then were off the pace in Japan.
It shouldn't happen this time. Ireland were superb in New Zealand and have the capacity to get better.
With all the rumblings about Foster, his assistants, Sam Cane, Beauden Barrett and cancelled press conferences, we shouldn't forget how good the Irish were.
A tough, combative, courageous, confident, skilful unit, led by a determined, innovative coach in Andy Farrell.
In recent memory, it's difficult to think of a better touring team to these shores.
They were arguably superior to the 2017 British and Irish Lions, and much more adventurous than the 2009 Springboks, for all the set piece mastery of that South Africa team.
Clive Woodward's England team that won shorthanded in Wellington in 2003 were a supremely well-drilled unit with Jonny Wilkinson at his peak but this Irish team is just as solid and has many more weapons.
Perhaps the nearest comparison is the 1998 Wallabies, with the likes of Matt Burke, Stephen Larkham, George Gregan, John Eales, Tim Horan and Toutai Kefu at their peak.
They completely outplayed the All Blacks at Lancaster Park, ahead 27-9 in the 77th minute before New Zealand managed two consolation tries. Rod MacQueen's team lifted the Rugby World Cup the following year.
The 1994 French team, previously the last side to win a series on these shores, were also special.
Emile Ntamack, Philippe Sella and Philippe Saint-Andre were key components of a glittering backline while Christian Califano, Abdelatif Benazzi and Laurent Cabannes were Tricolors' legends in the pack.
That team was unlucky not to reach the 1995 World Cup final, with their controversial semi-final loss.
