The best coaches can have huge impacts. Steve Hansen inherited a world champion All Blacks team and yet who would say he didn't have an immediate influence in making them better? There's been no single quality that he's brought to drive the team to a higher level, but his true value can be summed up in saying he's kept the squad harmonious, focused, driven and absolutely certain about what they are trying to achieve.
The same could be said of Joe Schmidt with Ireland. The Irish have been on the rise for the past decade. Their booming Celtic tiger economy has flooded the game with a bit of cash which allowed Ireland to vastly improve the respective strengths of their provinces.
Between 2007 and 2012, they were threatening to emerge from a nearly side to a genuine contender, but only made the breakthrough when they installed Schmidt as coach. Since he arrived, Ireland have become more resilient, creative and composed. Their depth has increased, and for the first time in 111 years, they defeated the All Blacks last year.
Schmidt has made a huge difference, as has Eddie Jones with England. He arrived in early 2016 after England had bombed at their own World Cup and parted company with previous coach Stuart Lancaster. Jones, experienced, smart, innovative and edgy, has turned England into the sort of force everyone feared they could be.
Jones hasn't changed the personnel much - he has changed the culture and attitudes within the team and found a way to allow the same group of players to get closer to fulfilling their potential.
"There's no surprise that the best teams in the world have the best coaches," former All Blacks captain Sean Fitzpatrick said last week.
"There's no surprise why Ireland has done so well under Joe Schmidt, England's done so well under Eddie Jones. I was surprised as anyone with the result on Saturday against South Africa, but the All Blacks have taken it to a new level, and it's the job of the other countries [to match the All Blacks], not just the Southern Hemisphere.
"We've seen it in the Northern Hemisphere, Eddie Jones is very focused on 2019, and he's looked at what the All Blacks are doing. They [England and Ireland] have looked at what the All Blacks are doing, and they're making changes, not only just in the game plan, but the way the players are playing."
The quantum leap Montpellier have made in paying Cotter in line with the best players, is expected to result in salary packages rising worldwide for the best coaches.
There has historically been a reluctance to consider coaches on the same pay scale as players and while the likes of Warren Gatland with Wales and Jones are believed to be the highest paid international coaches, their reported packages of around $1 million a year are well short of what is shelled out for the top playing talent.
What also shows attitudes about coaching are changing is the lack of former test players graduating to the international ranks as coaches.
At the start of the professional age, it was typical for former players to shift into coaching jobs in reasonably short order. There was a belief within administrative circles that good payers would automatically make good coaches.
But a snapshot of the nations currently ranked No 1 to 10 by World Rugby shows there is only one head coach, Gregor Townsend of Scotland, who played test football, and on other, Gatland, who was an All Black without winning cap. The other eight nations - New Zealand, England, Ireland, Australia, South Africa, France, Argentina and Fiji - all have head coaches who won't be remembered for what they did in their playing days.