How can people with private collections afford to have healthy breeding populations without an income. The highest income earner which also removes older males is shooting reserves.
Somebody has to pay for conservation, why not let shooters do it.
Trained marksmen is a term thrown around often. These are just people who are paid, it does not mean they are more accurate. Part of the guides job is to have the client test the accuracy of his gun, but they are more importantly checking the shooting ability of the client. If they doubt the ability of the client they need to make the shot easier, by getting closer to the animal.
Are you also concerned about the well being of animals in the wild. Their deaths are not humane and wild animals do not die peacefully like on Disney. The only animals which have humane deaths are those killed by humans.
A lot of people have this dreamlike notion of animals in the wild, where freedom is valued above all else, and wild animals are happy contented animals.
Using a lion as an example, if he survives cub hood in the wild, and doesn't die of starvation, getting lost, killed by hyenas or male lions taking over the pride as most of his sibling will be, he will be kicked out of the pride around 2-3 years of age.
then he must learn to hunt, or he will starve, and any male lion fidning him will do their best to kill him.
If he is lucky he will become a hunter, and meet up with some other males, and in a few years when they are at their prime they can attempt to take over a pride. If they are lucky they will do it with no bloodshed, if not they will be injured, possibly seriously, and even killed.
But if they are successful in taking over the pride they will have some stroppy lionesses to subdue as the girls object to their cubs being killed.
Once that is out of the way, they can settle down to mating with the lionesses and robbing them of their kills.
There problems are not over of course, as other males will be trying ot oust them, and they have the usual risks of being injured by the big game they are hunting.
After a few years they will be past their prime, and other males will kick them out. If they are lucky they will be killed during this oust, if not they are run off, often injured, to become nomads again, and will have t hunt until they get too old to chase game.
then its a slow death by starvation, unless hyenas finish them off first.
Compare that with a zoo lion, from cubs they are looked after, even hand reared if their mother can't do it. They are always fed, and any injuries or sicknesses are treated by keepers and vets.
They are usually separated from lions who might do them harm, and all they have to do is sleep and eat which suits them fine.
Eventually they will die of old age, which is far older in captivity than any wild lion lives to.
Few animals in the wild die of old age, most of them die quite nasty deaths.