This is a timeline for major development and changes in meta. This usually occurs when a new meta character or artifact set is released or when a significant milestone is achieved.
To zoom out even more from the above granular view, some of the biggest turning points of the game include: 1.0 when Venti and the game itself debuted, 2.1 when Raiden debuted, 3.2 when Nahida debuted.
It seems that whenever a new archon releases, the game will change. Can we say the same about 4.2? Focalors is a great unit, providing E hydro app and dmg bonus. But since Yelan/XQ already existed, some have remarked that her introduction did not 'revolutionize' the meta as much as Nahida, Raiden, or Venti did.
Moreover, it appears that when the designers were creating Focalors' demo videos, they did not showcase all the possible teams she could be played in, instead trying to tailor only to a few characters, which gave a false impression that she could be used in a limited number of teams (rather than being universal). Compare this to Nahida's demo which showcased her alongside many teammates, showing how versatile she is.
The truth is that Focalors can probably be used in more teams than Yelan/XQ since she is E dependent, has longer app, and does not require NA to proc. But perhaps there are not as many dps that need her if they already have Yelan/XQ (for example, Cyno is one of the few dps that arguably needs Focalors more than Yelan/XQ). This contrasts with Venti, Raiden, and Nahida, who are in many situations the best at what they do.
Remark: It is not often we highlight dps units, but Alhaitham's release is probably as revolutionary as Nahida's release given that Alhaitham can do a lot of the things Nahida can do for hyperbloom. Moreover, both are very effective at dendro app for hyperbloom teams (and hyperbloom is broken), and one can (almost) use them interchangably in some teams. Nahida's main advantage is her range and off-field app.
Rather than say each archon will change the game, it seems a more reliable pattern is that an artifact set in x.0 (the first version of a new region) can change the game.
Some people claim the meta shifts due to changes in the spiral abyss. If we focus really on Floors 9-12, with special emphasis on Floor 12, then there are versions that give certain characters an edge. But basically:
Versions 1.0-2.0: the Venti dynasty, where Venti was single handedly the most op support in the game as most enemies could be pulled and lifted by his Q
Versions 2.1-3.1: could be called the Raiden dynasty, as it saw the introduction of several gimmicks that gave Raiden an advantage in abyss such as electro rifthounds, energy manipulation, etc. During this period, while geo rifthounds were introduced to benefit Itto, Zhongli took a big hit as the rifthounds and various similar effects bleed through shields. Moreover, the new 2.5 shadowy husk enemies further penalize you for simply using a shield (they spawn a shield if you have a shield). While Zhongli fell in the rankings, Venti also took a big hit as during this period, many of the enemies in Floor 12 are just heavier and cannot be easily pulled and lifted by his Q. Seeing how these versions featured the addition of Inazuma, it is interesting that the Mondstadt (蒙德) archon does not fare as effectively in Floor 12 as the Mongols (蒙古) were thwarted by hurricanes when they tried to invade Japan centuries ago (during the Yuan dynasty).
As Zhongli and Venti fell, so did Ganyu as her two teams melt Ganyu and Morgana that rely on these archons simply do not work as well anymore. Zhongli and Ganyu teams are not hot during this era. Most people (including the FBI/CIA/NSA cybermob agents that crawl the internet) have given up on Zhongli and Ganyu.
The Raiden dynasty is marked by an increased shift to healing as a source of defense. During this period, the Raiden national team has shown its versatility. And as always, Xiao, Venti, Bennett are top tier meta. One of the biggest rising stars during this era is Itto, the new Geo dps. Itto is basically the best option against the geo rifthounds that appear during these versions. Moreover, unlike Zhongli, Itto relies more on his high defense to reduce incoming damage, rather than shields, which fell out of the meta.
Besides Raiden, other electro dps such as Yae, Beidou also benefit from the rifthound gimmick. Zhongli has a big feeling of being replaced. When Thoma was introduced, Hu Tao no longer needed Zhongli and could rely on Thoma as a better shield option. But since Zhongli had a boss like Hu Tao, it is understandable that Zhongli would retire and fake his own death anyways. Even Itto gets -20% Geo RES from geo resonance and does not really need Zhongli. So it is only for Xiao that Zhongli is not completely useless. Even when things turn to dust and after Ganyu and Hu Tao disappear from the meta, Zhongli will be remembered as the archon who protects his yaksha.
But then 3.3 came and Faruzan was released, who provides more anemo res shred than zhongli. So zhongli lost his job serving Xiao as well.
At this point, the only way to end Bennett's career in abyss is to penalize people for getting ATK buffs or healing. But it is unknown if Genshin has any intent currently to nerf Bennett.
Before Version 2.3, Geo only had what? Zhongli, Ningguang. It was a virgin element. After Version 2.3 with the introduction of Itto and Yun Jin, Geo became a more chad element.
Versions 3.2-: the Nahida dynasty, where hyperbloom teams dominate
We still live in the golden era of the Nahida dynasty, where hyperbloom, Nahida, Alhaitham teams dominate.
Focalors released as the first true hydro E sub-dps in 4.2, opening up many more hyperbloom teams. The introduction of new destruction characters with continuous self-drain (previously just Xiao) have also added to the possible teams that can be built, adding new styles of gameplay. Alas, the meta is still hyperbloom.
If anything, the introduction of the land of hydro only served to accentuate how broken hyperbloom is.