I don't mean this in defense of Sarah, but I remember her first few launches too, and people were so excited to support her, but there's going to be diminishing interest in any kind of influencer collab when it becomes a regular thing and not a one-time special. She seemed to think she could slap her name on whatever and it would instantly sell out, but even if it were all good merch from an ethical, admirable influencer, there's going to be less interest eventually.
As an example, the Holo Taco brand from Simply Nailogical has gone from rabid fans collecting every single thing she puts out, to most people being like "wtf another launch so soon??" as she's churning them out now. They're all good quality polish, but now that there are hundreds of items, people aren't feeling the drive to collect like they were when it was just ~30 polishes or so.