Except, having been a Parnis owner because of the hype on the Gen forum, I can tell you right now they aren't anywhere near as good as the reps on here. The movements are universally cheaper, the cases not as machined, and the dials often downright ugly. For example my Parnis BP was a 1mm to big in the case and the dial had mislaid, ugly, uneven markers at 4,5,6 and 9. Meanwhile my Batman GMT, while it had a nice bracelet, didn't have glidelock and the movement often lost time. Not to mention on the dial you could tell the hands and markers are cheap gilt.
While Parnis are for sure unbranded reps, they're being sold at 90-110 bucks shipping in. Which indicates to me they're probably 20 to 40 bucks at wholesale.
If we look at watchstation the cost they're paying wholesale is at least 100 bucks or more for most of th super Rep models. To be honest I suspect that's what your lower end Hamilton and the like costs, forget the Low end Seiko
Not slugging cheap watches, the Vostok Komandirskie us the best mechanical watch in the market under $100 but it doesn't stop the fact that having owned reps and Gen knockoffs, the reps are better
Moreover I deeply suspect many of the Rep parts factories provide most of the components for "Swiss" brands like Steinhart and Tissot, who are spending their real bucks on assembly and QC
I take your point on the Parnis watches, personally I have never owned one so it was an assumption and probably not a good comparison.