In the years when Jesus spoke these words, Tyre and Sidon, at one time great, rich and wonderful cities of the Phoenicians, were skeletons of their former glorious selves. As reported in Wikipedia, “the Phoenician civilization in the eastern Mediterranean slowly declined [in the first millennium BC] in the face of foreign influence and conquest; its presence endured in the central and western Mediterranean until the destruction of Carthage in the mid-second century BC”.
Jesus’ point is that those seeing “his mighty powers come into being” are faced with a choice. Either “they would change” or “they would not change”. Upon that decision, the future of those places would depend. Tyre and Sidon “would change” had those cities seen the “mighty powers” of Jesus. Tyre and Sidon still exist today. Chorazin and Bethsaida “would not change” even though those “mighty powers came into being” in them. Today they are archaeological sites.
“And you, Capernaum, you will not be exalted - until heaven. You will descend - until hell inasmuch as if, in Sodom, there came into being the mighty powers which came into being in you, it would have remained up to this very day.”
It seems that Capernaum firmly believed that it would “be exalted” until, one day, it would come to be “heaven”. Collective prosperity forever in fact. But Jesus foretold the opposite. He stated to them that – for one particular and vital reason – they would in fact “descend until hell”. The reason was: Change? No, thanks.
In the same way as towns, cities, islands and parishes look down on one another today, Capernaum looked down on historical “Sodom”, then and now beneath the Dead Sea. Capernaum’s thinking was that in no way would it ever come to be like “Sodom”. Not so, said Jesus, for one good reason. The reason was their strategy: Change? No, thanks.