His question makes sense to me, although I think it's been answered.
If they die, why not make it DH?
Answer: Because it's FFO. We don't have DHFFO regs in PA and nobody wants to make them. If it were DH, it'd have to be DHALO, and that would upset a lot of FF's.
If they survive, why is it stocked? (with the implication that it would then have wild fish)
Answer: In a good summer, some die, some survive. With C&R more survive. In a bad summer, nothing really survives, hence it's not capable of sustaining significant wild populations, and must be stocked.
Further, even if they die, the timing of such is highly dependent on the summer. i.e. our DH regs open it to harvest on June 15th. Water temps may not peak until August. This is a very popular stretch of water. A lot of fishing happens after June 15th before it gets too warm, which would be harmed by harvest.
With a more plugged in fishing population, the PFBC could do more individual managing of streams. For instance, have more reg categories, close thermal refuges, adjust the date of DH regs for each stream each year in response to local conditions, etc. They do this type of stuff out west with regularity.
But PA fishermen, by and large, aren't as aware about stuff like this. It's part of our truck chasing legacy. It's easier on the fishermen and those who enforce it to make a limited set of more easily understandable regs and hold to them. Even if it's not a perfect fit for each and every stream.