The poachers themselves are usually poor locals who get maybe a couple hundred dollars for a tiger. And if anyone ever gets caught, it’s going to be them. It’s the kingpins who make (tens of) thousands of dollars for every poached tiger. They are calling the shots and never get caught, because they can buy their way out of trouble.
They are the real criminals, often involved in all kinds of other crime as well (such as wildlife trafficking) and they are the ones who deserve the death penalty.