Matthew 11:21-2 Woe unto thee, Chorazin! woe unto thee, Bethsaida! for if the mighty works, which were done in you, had been done in Tyre and Sidon, they would have repented long ago in sackcloth and ashes. But I say unto you, It shall be more tolerable for Tyre and Sidon at the day of judgment, than for you. (parallel in Luke)

Not long ago a couple of people asked me about this passage: "If this is true, and Tyre and Sidon would have repented, why didn't Jesus go there and do some miracles? Those souls could have been saved, right?" I responded first by noting that Tyre and Sidon were likely among the first mission fields for the church, and that there could be little doubt that such signs were done in those cities at some point. I would still say this is true, but now would say that it would have no relevance to this passage. Jesus is not speaking of the Tyre and Sidon of his day, but of those cities hundreds of years before.

The first thing to notice is that Jesus refers to these cities doing the "sackcloth and ashes" bit -- not turning to him and submitting to his lordship. Sackcloth and ashes were "common public tokens of repentance" (Blomberg commentary on Matthew, 191), as they were for Nineveh. They indicated a change in behavior, but said nothing about the person's eternal salvation. All that Jesus is saying is that the cities would have done a moral U-turn, like Nineveh did. (And of course, Nineveh eventually reversed that U-turn and went evil again...we are not talking permanent effects here, nor of any lasting allegience to the true God.)

Taking it further, Jesus refers here not to the "modern" first century cities, but rather to the cities as they existed in Isaiah's time. His comments about Tyre and Sidon allude to Isaiah 23:1-12. (His comments about Capernaum likewise echo the condemnation of Babylon in Isaiah 14.) Therefore there is no moral dilemma about God not sending Jesus to Tyre and Sidon for a turnaround. The implications of such a visit are not as eternal (except in the sense that there are, or may be, gradations of punishment in hell), nor as relevant, as the question supposes.