Yes but with them not streaming there won't be any merch to sell. What separates Holo from Niji is that 1) Their merch cut for the talent is very good 2) The talent has a say to what merch they'll do 3) Why the talent is super busy behind the scenes is because they are the ones who comissions the merch especially if it isn't basic acrylic or sticker stuff. Holo right now gets most of its money from merch and sponsorships as the Holo talents are IPs of the company, not just streamers that work under them. Remember that YAGOO worked in Sanrio and you know how Sanrio is with their IPs (Hello Kitty, My Melody, etc.).
TLDR: Merch moves because the vtuber streams. Gura is UBER POPULAR but she worked hard for her to reach this point in her life where she just shill merch and her fans will lap it up. It just shows how great Cover's marketing is.