Lead in petrol is not, and never was, in the same form as two hundred and seventy round balls of #6 shot and lead in paint also was not, and never was in the form of two hundred and seventy round balls of of #6 shot either.
I quite agree that lead shot itself is quite harmless. Pure lead in any form is quite harmless, and it quickly forms a skin of oxide when exposed to air that prevents further corrosion.
But that is not what happens when a pellet is eaten. Stomach acid is a string acid. Drop a peice of lead into acid and it starts to dissolve and form lead compounds that are then absorbed along with all the other nutrients from your food.
And because of the mechanical action of your stomach the pellet is constantly being tumbled, so any Oxide layer is constantly being scrubbed off.
But of course you would never knowingly eat a lead pellet - but what about all that lead shot meat. If you cut away the shot meat on a phaesant or a duck you don’t have a lot left.
And what all that game that is going To the dealer and then into the foodchain?
We used to use lead paint, cigarrettes were advertised as good for you and plastics where the new wonder material. But knowledge and learning moves on, and so does technology.
High velocity steel cartridges do exist, and new brands are being developed all the time.
Yes Morris A, Model T Fords, 4 1/2 litre Bently’s etc are wonderful to drive and have, but if you want to do 500 miles on a motorway a modern car is do much better. Yes there is a place for my 100 year old Alex Martin. And frankly if I was able to afford several thousand for driven phaesant shooting then a bit more for Bismuth cartridges won’t stop me.
More likely I will use it on smaller walked up shoots as I currently do and put 50 cartridges a year through it.
For my wildfowling, I use a three inch chambered steel shot proofed semi auto and it works very well.