> Coax is due to other issues around CTB and/or the challenge that in Coax, you've got many frequencies running through alongside each frequency having different attenuation per 100 foot
Actually this is true for fibers as well. In DWDM (all internet links are DWDM, including fiber-to-the-home in most places) you have many frequencies running alongside and each frequency has differences in attenuation (though generally measured per kilometer, not 100 foot)
Optical light are standing electromagnetic waves. Which means they don't disrupt each other. Electrical signals aren't standing waves. They affect each other.
The difference can be put like this: how many X (electrical waves, but essentially everything, protons, ...) fit on the tip of a needle? (or in a cable)
1) electrical waves? Some finite number. Can be large of course, but ...
2) photons (ie. fiber signals)? ALL OF THEM. Literally every photon that exists in the entire universe would happily join every other photon on the tip of a needle nothing would interfere with anything else
