>>24982777... meaning that in some cases another person puppetted Oyabun than the original puppeteer. It's still a replacement even if partial.
And before this is blessed with a cheap getcha reply: Switching bodies during an offcollab or during an April fools stream or even as a one-off streaming concept (all of which were done in Hololive before) obviously does not count as a replacement because there is no intention to make the audience think the person is still the same.
I'm also not saying replacements are always doomed and bad, but it's obvious why under most circumstances it is detrimental.