As a farmer, I can tell you exactly why I wouldn't want to attempt to farm elephants for ivory.
The first problem would be acquiring the necessary amount of land necessary for a herd of elephants and then acquiring the actual elephants themselves but hey, let us look past this first near insurmountable hurdle here to see what other Proboscidean nonsense we would be dealing with here. Lol.
There is no truly domesticated species of elephant, so you would basically be attempting to farm multi-ton, temperamental, wild megafaunal animals that can easily flatten you into a red paste. Not only that but elephants are some of the smartest animals on the planet to boot. Have fun dealing with a prey animal with more brawn and more brain than any other domesticated mammal on the planet.
The fact that there is no domesticated species of elephant is especially interesting to note considering humans have actually used elephants throughout history (e.g. as war beasts, beasts of burden and status symbols) across numerous civilizations but despite this, no truly domesticated elephant population has ever been established. Probably because the logistics of truly domesticating these creatures are unfeasible due to their long lifespans, dangerous nature, high costs and intense resource demands.
Also, since elephants are part of the clade Afrotheria, they don't have scrotums but instead have internal testes. This would make them much more difficult to castrate compared to any domesticated mammals and means dealing with excess males would be a costly and time consuming endeavour. You would be looking at a major surgical operation each time you need to remove an elephant's nuts, never mind the fact that since elephant castration isn't exactly in high demand, there will barely be anyone available for hire with the knowledge and expertise needed for such an operation.
Speaking of time consuming, since elephants are so damn big, they are slow growing creatures. The gestation period is 18-22 months for Asian Elephants and 22 months for African Elephants. So from when you put your bull elephant onto the females, you are going to basically be waiting for 2 years for the first generation of calves to be born. Then it will take another 2-3 years just for those calves to be weaned. Then you are going to have to wait for at least another decade until those calves are sexually mature. It takes around a decade and a half just for your first generation of calves to become adults. You could have had at least over a dozen generations of pigs, goats and sheep in that time. Probably about a half dozen generations of horses and cows too.
All of this to breed an animal for it's tusks which are a couple of highly specialised incisor teeth that are embedded all the way into the elephant's skull. These things have nerves and removing them is excruciatingly painful for the elephant. So you would have to heavily sedate a dangerous, multi-ton, temperamental animal and have yet another specialist surgery for removing part of the tusks. Considering that the open nerve endings on the newly cut open tusks can easily become infected then your elephant will probably die after this operation anyway. Then you will have to deal with disposing of a multi-ton carcass. As for killing the elephant instead well then you might as well have just shot it in the wild and avoided all this elephant farming tomfoolery... and you will still have a multi-ton carcass to dispose of.
So compare the financial and time investment costs of all this compared to simply grabbing a big gun with sufficient ammo, killing a jumbo and plundering it's corpse for ivory then you can likely see why poachers would much rather poach than farm these creatures.
