Holos debuted each year:
>2017
Sora
>2018
Roboco, 1st gen, Miko, 2nd gen, AZKi, Suisei, Mio
>2019
Okayu, Korone, 3rd gen, CN1, 4th gen
>2020
CN2, ID1, 5th gen, EN1, ID2
>2021
EN2, 6th gen
>2022
Damn you, Omega.
>2023
EN3, DV1
>2024 (so far)
EN4
Cover was in its accelerate age early on as to establish a base, then has slowed down since in order to make sure all talent is supported. I do think that they're going to be accelerating more than these recent years soon, in order to aggressively expand into new markets. The truth as to why EN seems to be the only gen still getting new members consistently is because its the only branch that needs that. JP is well developed already, and should focus growth efforts elsewhere. ID really hasn't seen as much success as the other branches, and it's growth is mostly contained to two members; one of which only got there due to finding success in EN spaces. EN is still in its growth stage, thanks to a certain someone thinking it'd be a good idea to take nearly 2 years to debut a THIRD GENERATION, and will probably need at least a fifth gen for it to go into its final phase. Device is weird. No one knows what its purpose is.