No, utlity poles are MUCH, MUCH cheaper than undersea cables. Not even close. Plus you can run 216-strand on telephone poles whereas undersea cables (due to repeaters) are generally 6-strand and almost never more than 12-strand. Utility poles are cheaper even including the cost of the poles themselves.

However in order to put up utility poles you need a ROAD in order to get vehicles to the poles for maintenance. That's why you see offshore cables: when there are no roads through politically-stable territory.

Look at Alaska: the fiber runs overland all the way from the southern coast to the northern coast because the oil companies built a road next to the pipeline. Then it goes offshore along the arctic coast because there are no roads between the coastal communities.

Once you have roads and political stability, utility poles win every time. Underground is more reliable but more expensive. Undersea is insano-expensive.