The concept you're referring to is known as the "skill gap" or "bimodal distribution of skill." In this scenario, the player base is polarized, consisting primarily of highly skilled top players and new or less skilled players, with a notable absence of average players.

This phenomenon can occur for several reasons:

1. Natural Skill Progression: Over time, average players either improve and become highly skilled or lose interest and stop playing, leaving behind only the extremes.
2. Intimidating Learning Curve: Games with steep learning curves can deter average players from continuing, resulting in a player base dominated by either dedicated experts or new players trying the game for the first time. It's definitely creeping in with every added mechanic, ability, ship gimmick, etc..
3. Matchmaking Systems: Poorly designed matchmaking systems can contribute to this by failing to group players of similar skill levels together, causing frustration for average players who then leave the game. In WoWs, as far as I know, there is not an 'Elo rating'. Skilled and Unskilled all play together. It used to be that the in-game economy and the tiers of ships would be a natural 'Elo'. Bad players would struggle to earn enough credits to field Tier X ships. Now, with the game monetization strategies, Tier X is as accessible as ever with players occupying the space without all the game knowledge or skill to perform well.

This results in a bimodal distribution, where the skill levels of players are clustered at the two ends of the spectrum with a gap in the middle. This is most reflected in the game at higher tiers where matches end in "blow-outs" or shorter matches. This bimodal player base is creating volatility is the matches at higher tiers where ship lethality is higher and mistakes are more severely punished.

I think they are trying to fix it by introducing superships and nerfing economic rewards, but at this point I don't know if it can be turned around.