Maybe we should differentiate between an average life span of a hatchery bird vs other types, i.e., breeder stock. I seriously doubt the hatcheries will change anything they're doing. After all, seems it would cut into their business if all the birds they sold lived to be 7-9 years old.
My oldest two hatchery girls are approaching 6 years old now, but neither is laying and one is Reba, who I know has nasty gunk building up inside her. Then I have two Brahmas who are approaching 5 years old, from the same hatchery, and a banty Cochin and one Silver Phoenix as well from there. None of those are what most folks consider production layers, though, so maybe they have a shot at avoiding the internal laying thing. The bantam Cochin has been egg bound twice, though. Hatchery hens just don't seem to be made of strong genetic material, in general. I don't plan to buy from the hatchery again, not unless I have a specific reason to get one or two birds, like for a broody whose eggs didn't hatch or something.