The fiber ran right now is nowhere near reaching it’s theoretical usage. The issue is now, and always has been, having someone actually run it. That costs money. It’s also a bit more physically vulnerable, and requires some more care to not destroy, which makes the actually running it part a bit more expensive than copper in many circumstances.

This won’t change anything for 99% of new fiber deployments, and practically doesn’t make any difference for existing fiber deployments either. The actual media is still 100x more capable than anyone’s end termination equipment outside of a lab.