>>65205195Unlike nijisanji which benefits from cutting dead weight, hololive's characters are fewer in number and have larger customer bases that like them so it benefits hololive to keep the voice actress employed even if she's not really doing anything beyond rubberstamping merchandise and doing pre-recorded concerts to keep her fans occasionally ball-tickled.
It's like how Kana Hanazawa never 'graduated' but gets less work over time.