tell me why

You're assuming a guy is going to run stock heads, which nowadays is pretty unrealistic. You're also assuming a Chevy guy isn't going to use screw in studs in the first place. Heads with screw-in studs have been around for years & unless you're doing some type of period-correct piece press-in studs are useless so the conversion wouldn't even be considered.
Also you're looking at brand new stuff when the fact is Chevy stuff is a dime-a-dozen. I had aguy GIVE me a big-block stud girdle & screww-in studs. The best SS roller rockers Comp Cams make are listed (Jeg's) at about $330 so you can see just how cheap Chevy stuff can be---they're giving it away!
As I said, from an engineering standpoint Mopar IS a few steps ahead but the willingness (?) to share accurate info, not be blinded by "purity" of facory correct parts & the sheer vastness of knowledge of things Mopar just doesn't seem to exist....