>>9712142Because writing lyrics & music, recording, mixing and preparing youtube videos (even the simple ones where it's just still imagines with effects on them) for songs costs a lot of money.
It's believed that Cover does do that for a small amount of the Holos (eg Azki, Irys) but the rest have to do it themselves.
For a relatively small company like Cover, there is a lot of risk associated with spending company money on song projects that might not catch the imagination or the algorithm, leading to poor sales and losing money.
There would also be issues of which holos get what amount of attention and money. Does Watame get help making a full album while Subaru or Akirose have to do with singles? Which of Sora, Miko, Suisei and Azki get priority, would someone like Botan or Kronii or a HoloID wanting to make a song get kicked to last because they aren't a "serious singer" like the others? Nene, she's clearly one of the most talented singers in the entire company, does the Japanese fetish for seniority mean she has to wait 5 years for a full album worth of songs?