Yeah, I guess I just got unlucky. My ZSTs are holding up great, though they don't sound anywhere near as good as the ZSX.
This is the most I've paid for a "budget" IEM, and it just so happens to be my very first pair with a failed driver. It's disheartening and makes me hesitant to pay more than like $20 again for Chi Fi.
Too bad, cuz I've been planning to eventually buy Moondrop Starfields, but QC for budget Chinese headphones seems pretty sketchy.
Moondrop is one of the chifi companies that has tight QC and consistent tuning between their products, and i haven't found them secretly changing tuning/drivers on their existing lineup. usually they would just discontinue and make another product if they decide to change something. so I'd say if you decided to go for the moondrops it'll be a safe choice.