Indeed, I think a lot of them are realising that if they go a lot of their fans will follow them so they're more open to the idea compared to before when maybe it wasn't as guaranteed.
There's always advantages to being indie or corporate, but having that fanbase follow you going back to indie eliminates a lot of the biggest disadvantages of being indie so I'm not suprised that so many corporate vtubers are leaving.
mumei (the song) is one of the EN songs that really touched me, and I've played it over a thousand times according to my stats (over two thousand if you count a couple of remixes of it).
It also says in the description that it has been translated to Japanese by Bae, I don't think a hiatus announcement would need to be translated but hope I'm wrong