Sorry I missed some of these comments. I'll just do one big reply with some thoughts, and then I'll leave it alone. You guys (and others) can feel free to have the final say.
It's probably important to say that GLA don't refer to 'cohesion' the way almost every rugby journalist and commentator does. The term, 'cohesion', as used by GLA, refers to a level of understanding, which can be objectively measured. But it's not simple to measure. My understanding is that GLA use a complex algorithm, which takes into account three main areas of understanding: 1. the understanding between players (their shared experiences, combinations, etc); 2. a player's understanding of their roll within a team (e.g. how long they've been playing a certain position, etc); and 3. a player's understanding of the program (e.g. pathways, how the team works, the game plan, defensive structure, relationship with current coach, etc). All 3 affect a team's capacity for cohesion.
GLA also measure the cohesion of teams within the team. So for example, the level of understanding between the forward pack is more significant than the shared experience between a prop and a wing. Likewise, the understanding between the front row in itself is highly significant, etc.
How cohesion affects the performance of an individual system is nothing new. There are plenty of academic studies outside of sport on this. GLA are just the first (to my knowledge) to apply it to sport.
To suggest that GLA's measured level of cohesion has simply correlated with the Wallabies decline, rather than been a significant cause, is to discount literally thousands of hours of data analysis across not only multiple rugby teams, but multiple team sports worldwide. Their research really is that extensive!
I think there's probably other factors with the 2019 Springboks that we're not seeing. For example, not only were their selections more consistent than most for about 2 years prior to the world cup, but about half their entire squad had come through the Stormers set-up at some stage. Likewise, I think more than half of the starting 15, and most significant of all, 6 out of the 8 starting forward pack! And how important was their fwd pack in winning?! Coming from a single system makes a big difference to a team's level of cohesion. It's like all those players coming from the same family, or working for the same small company, or being familiar with operating an Apple iphone as opposed to an android. There is ingrained habits and a shared understanding. So already, that's 2 out of the 3 main ways of building cohesion just in terms of the level of understanding among the players.
Likewise for France. Apparently, their performance has not been any surprise to GLA. They claim they're tracking according to their numbers. Like SA, part of the reason has been their consistency in selections, but another reason I'm sure, is that a core part of the team has come through the Toulouse set-up. And Toulouse is not just an ordinary team, but a highly stable and cohesive team in itself (according to GLA). In any case, again, that's 2 out of the 3 main ways of building cohesion just in terms of understanding among the players. GLA also credit other factors in contributing to their cohesion, such as their overall stability and pathways.
The point is, it doesn't matter whether any of us think a particular team has the capacity for a high level of cohesion or not, what matters is whether GLA thinks they do, and whether their numbers are consistent with a team's performance. Because, while teams sometimes underperform, if GLA's numbers are predictive of performance, then we should be listening to them when they tell us what they're consistently finding to be the cause of that performance.
It's not really a chicken and egg thing. Generally speaking, the order goes: playing together over time increases a team's capacity for cohesion. Higher levels of cohesion improve a team's performance (unless a team underperforms). In this way, cohesion contributes to performance, not the other way round.
Yes, a newish team might perform well, which leads to the players getting re-selected and playing together longer, which then increases their capacity for cohesion. But no one denies that skill/talent also contributes to a team's performance. However, it's not their performance per se that contributes to their level of cohesion. Cohesion is not dependent upon a team's performance or success. For example, an u15 team might have a higher level of cohesion than other teams, but may never win if those other teams are a bunch of professional teams. However, the GLA algorithm won't suddenly suggest the u15 team must have lower levels of cohesion than other teams, or that other teams must have higher levels of cohesion just because they're able to beat the u15 team.
Talent/skill and cohesion are two seperate factors that influence the performance of a team. Both contribute. However, among professional teams, GLA have found that cohesion is a stronger predictor of a team's performance than their level of skill.
And in fact, GLA have found that cohesion affects whether a player will be able to perform to their skill level capacity or not. This is why a team like the Crusaders or Storm can drop a 19 yr old kid in, and almost immediately, they look like they're test quality. Or why a good player can move to a new club, and all of a sudden they're not so good anymore. Cohesion and stability within a team can accelerate (or hinder) a player reaching their skill capacity. So while skill affects performance, cohesion can enhance the potential impact of the skill level on performance.
The Wallabies might have significant talent coming through our pathways, and yes, their cohesion levels and performance will increase as they play longer together, but it won't be enough for consistent success if cohesion levels are below that of other teams. Or to put it positively, we will be able to better help our talent reach its capacity if we have a system that intensionally builds cohesion at all levels.
But how does a team build cohesion if it relies on consistently selecting players who are playing well? How can they be consistently playing well before they build cohesion? The simple answer is, while you do need to pick your best players, sometimes you also need to 'pick and stick' in order to build cohesion and allow players to reach their skill level capacity. Having said that, building cohesion is not just limited to consistent selection. In this respect, GLA have found that cohesion is highest for teams that build talent from the ground up, rather than import it from a different system.
On Melbourne Storm and Qld having some of the greatest players to ever play the game, the question is, would those players have been as great if they weren't playing alongside each other in such a stable environment? What are the chances of three of the greatest players in Cronk, Slater, and Cameron Smith all playing together for the Norths Devils at the same time prior to the Storm? Were any of them predicted to be as great as they were? I'm betting not. While skilful players make a team good, I think even more so, a stable and cohesive team makes good players better.
Anyway, they're just my thoughts I wanted to get out. I know I've said way too much, so now I'll just keep my mouth shut for a while, sit back, and watch you guys tear me to shreds.