>>31736426pretty simple, they didn't have a Coco-equivalent iconic EOP panderer in their JP branch (Oliver came after Lazulight debuted and Rine didn't stream much nor was she willing to pander. Hana Macchia was the closest such figure but she had a menhera moment from not wanting to be ahead of her ID branchmates who were languishing in <50k sub hell), and they failed to capitalize on the first-time buff on the EN market before holo did.
Despite holoEN having largely fell off in popularity, the attention they received during their massive boom ultimately directed publicity towards the entire company as a whole and the JPs and to some extent IDs, having better work ethic, have been very much willing to capitalize on this publicity and therefore skyrocket almost every member to frequent 5-digit CCVs and million subs.