I shot 2oz #5 lead out of my 10g gauge for 2 decades... its crazy deadly and accounted for around 100 birds. That being said, about 1 out of 8 to 10 slam dunk kill shots with the 10g the bird got away. Not because the lead didn't have the killing power at reasonable distances, but just because the head and neck slipped through the pattern.... that won't happen with properly choked #9 TSS. There just isn't any way you arent going to get at least a dozen pellets in the brain or spinal cord at 40y and in with the pattern density TSS throws with 1.5 oz. It's that good, it really is.
If you are shooting at reasonable distances (40y and in), TSS is FAR more ethical due to fewer crippling losses. Pull the trigger, punch the tag. No more shooting at 6 birds to get a 4 bird limit like happened with lead.
Again, this is at reasonable distances (40y and in)... beyond that TSS has the penetration to kill at 70 or even 80 yards, but the lack of pattern density is going to result in just as many crippling losses as kills... which just isn't ethical.
I started turkey hunting in 1971 or 72. I didn't kill (or shoot at) a bird until 1988. They were few and far between in the mountains of ETN during those years, and I made a BUNCH of rookie mistakes.
Since '88, I have killed a bird or two. During that time period, I "missed" two gobblers that I badly misjudged the range of. They may have been wounded, but showed no signs. I am certainly not proud of taking those shots as they were not in ethical ranges.
Absent of that, every bird (except one) I pulled the trigger on with my 12 ga and lead #5 dropped in their tracks and were DRT. Most didn't even flop. The bird that I had to shoot at a second time dropped his head at 18 yds as I was pulling the trigger. I grazed him and he went straight up and flew. I shot again, and he glided another 20 yds where I found him dead. Hard to have much more ethical results than that with a pretty darn large sample size.
TSS is great. I have partaken of the koolaid and own a bunch. I have used it to kill several birds. I'm convinced in my results that it is NO BETTER than my favorite lead loads in my 12 ga. Dead Right There is dead with either one. There is no doubt in my 20 ga that TSS is the load of choice.
The prices I am seeing right now for TSS, when you can even find it, are $10/12/shell. That is a load for some folks budget. IMO, it is a stretch to imply that TSS is some magic bullet and a hunter is not ethical if they aren't using it. Turkeys were killed for decades with lead, and, it will kill them just as dead right now. Ethical shots are determined by knowing what your gun will do, and limiting actual shots to where you have sufficient pattern to kill the bird in its tracks.
And, it can be done just as well with lead at least in the larger bores.