The criminals who do the deliveries also "have an interest" in stopping it (threat of prosecution). This is a complete rehash of the gun control argument: Whether you believe people who commit crimes are responsible for their actions or if the blame should be shifted to corporations or the ever-overused scapegoat "society".
What's sad is that ultimately the prisoners are going to suffer with less yard time. In my state, they had a couple fentanyl laced letters, so they blocked all prisoners from receiving letters (they get a photocopy). I believe that applied to pictures too. They got rid of all in person visits and replaced them with video calls, either blaming covid or staff shortages.
There's basically no way to prevent drone drops without building a canopy.
If they don't care, some government will force some worse regulation on them.
... and DJI is a Chinese company, where the government have no shame making up ad-hoc arbitrary rules.