Those don’t look like $500 open mold frames.
I know you mentioned open mold yet I wasn’t referring to such. As you point out a pro tour frame at half the cost of the equivalent Specialized Tarmac. That’s budget. Sorry for any confusion. The Tavelo, Seka etc I mentioned are not open mold as far as I know.
Maybe I misunderstand but I think;
there are open molds anyone can use. Then there are molds some Chinese company’s design . Then there are the molds from last year, designed by the biggies that don’t quite make it to trash compactor.