This incident in the Gerasene’s requires some entry understanding. And, it can not be understood properly out of this context. But, the context is not going to be comfortable (accepted by) to some traditional understandings.
Nevertheless, for consideration. To understand this event, you need consider the incident at Babel, and Deuteronomy. The people (nations) were divided up, and boundaries allocated' and the sons of god were put over these nations.
DEUT 32:8 When the Most High gave to the nations their inheritance, when he divided mankind, he fixed the borders of the peoples, according to the number of the sons of God.
The ‘sons of god’ ended up becoming the ‘gods’ of these nations. And, Gerasene was one. Jesus had been performing miracles in Gods nation - Israel. Exercising authority in the land allocated to Abraham, for Israel, the land set aside for God and his people.
Here in Mark, he purposely set out to travel into another land. A land that was essentially under another god (lower case ‘g’). We see the first reaction to this in the storm ...
MARK 4:7 And a great windstorm arose [snip]
The word translated windstorm here, and storm in the KJ, is the word lailaps, which is more than ‘just’ a storm. It is a violent tempest, that is, outside of ‘the natural’. Similar to the ‘storm’ we see in the book of Job that killed Job’s sons - and Satan was the instigator of that as well.
The exercising of authority over demons, in the land ‘under’ another god, was a message. Jesus was saying, (demonstrating) that He had all authority, in any land. And the people there were scared, they recognised this, but more, they realised the significance of this.
It’s important to note that this was the first demonstration of Jesus’s authority outside of Canaan. It was significant.
Now' as to the ‘pigs’ (an unclean animal, so you know Jesus wasn’t in Israel!), you also need to understand the significance of this - to the people in Gerasene. Pigs were specifically set aside as the animal used in sacrifices to their god. They were sacrificed by being thrown off a cliff.
Now appreciate the reaction - another God was ‘messing’ with their god - and demonstrating authority! It had nothing to do the farmers losing revenue - at all. That’s just ‘westernised interpretation’ which simply doesn’t ‘work’ when interpretating a Jewish book.