While this is really neat, is it actually much of a problem? I mean, fiber is cheap and you can put many strands into a not particularly thick cable, and there

While this is really neat, is it actually much of a problem? I mean, fiber is cheap and you can put many strands into a not particularly thick cable, and there's DWDM as another comment says. Is actually running into the limits of the fiber a frequent occurrence anywhere in the industry, like in the submarine cables?