>>58747413Video editing is extremely time consuming and much more difficult than streaming, especially when you're on your own. But the biggest reason is simply that videos aren't paying that well anymore compared to livestreaming thanks to superchats / donations / memberships, so it's more difficult to actually make a living from it.
Of course, there's still plenty of content creators focusing on videos only, but a "pure" Youtuber cannot possibly compete in the amount of content he can produce compared to a streamer unless he's willing to spam his channel with short, barely edited low effort videos.
This isn't exclusive to vtubers too, the current "top fleshtuber meta" is usually to stream on Twitch while commissioning other people to edit videos for them on Youtube.