Yes. For cocaine, for example, they have large farmer networks that cultivate coca, harvest and process it lightly (drying, etc.). The cartels then finish the process and undertake the logistics of shipping it across borders, into the US, or across the Atlantic into Europe.

This logistical leg is where most of the work is done since you have to:

Maintain large slush funds for bribing law enforcement.

Run workshops and technicians that strip civilians cars, embed cocaine in the nooks and hand them over to American civilians to drive over the border.

Hire engineers from Pakistani universities to build narco-submarines in riverine deltas, which are then used to cross the Atlantic for European supplies.

Maintain contact with your African coastal syndicates who have another trans-Saharan route for getting drugs into Europe.

Run payroll for your workforce (this is a business after all).

Maintain a decently trained fighting force to slaughter enemies that encroach on your turf. Or informants, uncompromising cops, politicians, etc. This includes training, paying, initiating them, and hiring good experienced fighters. Right now, it's credibly reported that Mexican cartels are volunteering to fight in Ukraine to gain experience with drones and other UAVs to expand their war-making capabilities.

Hire chemistry undergrads from local STEM universities to turn synthetic precursors from Asia into fentanyl, etc.

So, just like African cocoa farmers and American growers see just a tiny slice of the profit the end-products produce, the cartels are in the logistics & firepower business; they've outsourced a huge chunk of the business to growers, just like their peers in the chocolate and grocery business.

Yes, the average heroin farmer is making more money than a wheat farmer, but he sells it to someone who can get it to America.

yeah, this makes no sense. Don't the cartels control all aspects from production to distribution?