If you're going to lay a fiber across the oceans, then yeah, that capacity is going to approach the Shannon limit, but at some point there is a calculation to b

If you're going to lay a fiber across the oceans, then yeah, that capacity is going to approach the Shannon limit, but at some point there is a calculation to be made about how expensive it is to use all that capacity vs using multi-core fibers or just laying out more fibers. The economics of it are pretty interesting. A single fiber (non-submarine) is about ¢8 a meter in raw cost, and it said that they laid out so many during the telecom bubble of the late 1990s that there are still many unused (so-called dark) fiber networks throughout the US. See for example https://www.ofsoptics.com/lighting-up-dark-fiber/ https://www.ofsoptics.com/lighting-up-dark-fiber/