It may help to start by comparing a wired connection to wireless first. The cable that comes to your home uses much the same frequencies that are used all the time over the air, but cable company can use the same frequencies that are used outside the cable inside the cable but lets them use the whole spectrum or at least most of it because you will always have a certain amount of leakage. Even in a new cable system, you will have lose connections that leak RF, the cable company knows this and the put special frequencies not used outside the cables in the cables that can be easily detected when they leak and drive vans around mapping when they spot that frequency. then they can check for lose connections that might be leaking other frequencies also.
So what you need to understand is that each run of cable has a whole spectrum of frequencies allowed inside that can be shielded from outside interference, and therefore will always be better than a wireless connection in almost all ways when the cable is not having an issue anyway.
The cable company can also divide the cables going to different areas/nodes to reuse the same frequencies for things like VOD so a frequency on one node can be used over again on every node for a different customers VOD stream for instance. This is something wireless can not really do since it would run in to interference in the airways.
Now lets get to fiber, Fiber has a big advantage over copper cable in that you do not have to worry about electro magnetic interference at all, no issues with grounding or lose connections allow your frequencies out or other frequencies in to the system. It is easier to diagnose issue on the fiber using sensors that pick up back scatter reflections on the fibers. and currently they can support 400mbits per light frequency on the equipment that some providers use, with 80 frequencies per optical DWDM device, and I am sure they are already doing 1 terabit per frequency on newer lap systems etc with also more than 80 frequencies in use.
The fact that you do not have to worry about electrical interference is a big deal, you either have the light levels you need or you don't and no interference to worry bout, you do not have to worry about electric spikes from storms or anything like that being carried over the fiber and it is also much easier to run equipment that would detect anyone messing with the fiber or trying to TAP it.
So wireless might be nice and getting better all the time, it may be enough bandwidth today for some people, but will not be better than a direct connected wire or fiber.