Because the problem isn't actually the jury, it's the structural incentives that mold the system as a whole, including the judiciary.

People like to point out that this applies to trials for violent crimes etc. too, but it was really the war on drugs that did this, because it required the government to prosecute crimes with no victim -- the drug buyer and the drug seller have no reason to turn each other in, as opposed to the mugging victim who can be generally expected to go straight to the police.

Because convicting people when there is no cooperating victim is so much harder, they went and corrupted the system in order to make it easier, and here we are.