[jeffreyrogers]

Because there's only so much wireless spectrum and at some point you saturate the link. Plus interference from other carriers reduces the capacity of the link.

I'm not saying it's impossible, but it's also not obvious to me that wireless is better in dense areas, especially since the main cost in wired internet is laying the cable in the first place, which is easier to do cost effectively when you have an urban market to offer service to.

[DenisM]

How can there be interference between different carriers, if each is using their own spectrum?

[jeffreyrogers]

It depends on whether it is licensed or unlicensed spectrum. Some of the technology is in ISM bands that anyone can use.

In either case, the channels still have capacity limits. I'm not saying it's impossible, which is partly why I brought it up in the first place. I was hoping someone more knowledgeable would chime in. The main advantage wires have is you can just run more of them when you reach your capacity (or in some cases you can just change the hardware at either end of the wire to newer technology).

[DenisM]

Are there any US carriers that are using unlicensed / shares spectrum?

The bandwidth is only limited per tower, you can easily double the throughput of a given area by doubling the number of cell towers (and reducing power to avoid interference). It’s a lot cheaper to build a new tower than to run new wires to 200 homes (permits and all). On top of that 5g gives 10x bandwidth over 4g in the same band.

[topranks]

Meh.

You can have 1,000 wires in a bit of pipe, effectively 1,000 "spectrums." The air will always only be a single spectrum.

Cell division does not scale infinitely, and becomes more and more complex to manage.

Running cable you do once, then you can benefit for a long time. Wired will always be the better technical solution, and more economic one, in built up areas.