Even when they sell the propriety parts, they will be discontinued eventually (usually within a year in the vape industry). And in time, the mod may survive but be rendered practically useless because the bottle breaks, the carrier warps or cracks, or the holes in the plastic carrier strip out from removing and installing the screws too many times. Unless you stock up on parts when they are avaliable, the propriety thing can very likely be a death sentence for the mod over time.
I just zoomed in and noticed the carrier has metal inserts for the screws (nice thinking on their part), that negates one of my points, but my main point is still valid.
True, I would have purchased at least 2-3 of each just .n case. That should last a while. I still hate proprietary parts though. I understand them trying to make a device better but try and get away from proprietary and use parts that can be easily accessable.