These aren't business decisions taken to corner the money laundering market for Mexican cartels. It's more like Mexican cartels try all the banks to see which ones they can launder money through, and when they find one with poor controls that allow it they double-down on using that bank until their activity is stopped.
Maybe at the country level they were happy with the transaction fees, but I would be surprised if it went any higher than that and certainly wouldn't be worth the risk.
Maybe at the country level they were happy with the transaction fees, but I would be surprised if it went any higher than that and certainly wouldn't be worth the risk.