>>1350334The cut for voice is officially published to be at 50:50 and nijisanji already cut off the middleman (Booth). Mayuzumi hardly ever enables SC and he's comfortable enough to give away 1 million yen over a luck based game. He also said per month voice sales generally trend upwards (tamaki collab)
The video you linked was a basic lecture from Deron regarding vtuber income for aspiring vtubers or curious viewers, why the fuck would she publish company rates there. Also if you actually watched the damn thing you see her deeply thanking members for her wellness, indicating that her membership or SC income is significant. What she DID said is yes, nijisanji does take a cut (duh) and such is the cost of being in a company. Also Kaede has severe spending habits and is known to blew her money on luxury fashion items.
On the flip side, Kenmochi who's nortorious for not doing any voices said he's doing fine off superchat alone (no membership).
For a more extreme example, take Kirame, who you would call a "bottom-tier niji" was a poorfag and she is now able to give presents back to her family.