Yes operating a non fibre cable is too expensive and does not make sense. Fibre cables on the other hand have remained operational over a long time. AFAIK there

Yes operating a non fibre cable is too expensive and does not make sense. Fibre cables on the other hand have remained operational over a long time. AFAIK there are no fibre cables using electro optic repeaters operational anymore. But the earliest fibres which used optical amplification are still operational. This is the beauty about fibre communication. You largely only need to upgrade the endpoints to increase your throughput.