My daughter has dropped foreshore geese with her 20 bore shooting steel . I do not see your point from a practical stand point regards the 20 bore . BTW tungsten handloads in the 20 kill ever bit as well and geese as high if not a tad further than 10 bores with lead .
"IF" CIP dropped the whole velocity thing and just stuck with pressure none home loaders would have easy access to faster and better steel loads .
I do not think we have much choice with the 410 but small shot bismuth keeping ranges pretty much as they have been with lead .
One thing is for sure , the alternative is not going shooting ! Folks say " cost is too high " Yet very, very few do the bulk of a seasons shooting spending more on ammo than fuel when they go shooting . I note very few turn up in a little economic car , so costs are obviously not as important as is made out regards ammo .
I would be interested to see a 20 v a 10 to be honest