This was 10 years ago, but the data closets had SFPs on the switches for the fiber. So the cost of the "media converter" was really low - just needed a few. The

This was 10 years ago, but the data closets had SFPs on the switches for the fiber. So the cost of the "media converter" was really low - just needed a few. There was existing CAT5 in the walls, all of the runs would be well less than 100 m which is why I brought up the comm closets. For a new builds, I have no idea for the cost difference. But for the insane number of buildings wired with CAT5/CAT5e/CAT6, this solution works well. Trying to pull fiber to replace CAT5 (as in without removing the drywall) would be very expensive and likely to damage the fiber.