Again, it seems as though there is a misunderstanding in the word "productive."
The hatchery birds will lay more eggs more frequently earlier in their lives, but overall, the heritage birds will lay more eggs for a longer period of time, making them far superior in the egg-laying capacity.
As for the meat processing, they may take a smidge longer, but again, the carcass size will be far larger than a bird bred for production.
Unless, we speak of course of the Cornish X. Personally, I love having a few of those available as dinner. I might have to get back into those for a 6 week dinner.
My two best layers right now are 6 yrs old and are DP birds that have been laying 5 days out of 7 all year except for molt and broody recovery. They lay right through the winter without the aid of lighting. They and their former flock mates have been keeping this level of production for all these years now, with just this past year seeing some of the birds this age needing to be culled for nonlaying. I'm doubting these WRs were bred specifically for production, nor the BAs or NHs I've had either. I think they are referred to as DP, though after seeing carcasses on these three breeds I only consider the WR worthy of true meat qualities.
I agree there is a misunderstanding about the word "production" where some are imagining one is referring to a leghorn, RIR, sex link variety of hatchery bird, which I am not. I am discussing dual purpose birds with excellent laying and good body weights. I agree with you on those production breeds, which is why I never get them any longer. They aren't worth the feed past their first season for any reason as they fall short on anything I find desirable.