I've actually had to deal with fiber for the first time in my career recently and it was actually easier and cheaper than I imagined. I think my take on costs was about a decade out of date and things have gotten pretty affordable these days (for 1Gbps at long range at least). Probably all the fiber to the home providers have pushed the economies of scale on these things.

But here's sort of an example of what I'm talking about.

https://www.amazon.com/Gigabit-Ethernet-Converter-1000Base-L...

So the cost is pretty low if you wanted to terminate with these (these things aren't too loved in networking circles, but I can vouch that they do work), then the biggest difference is the cost of bulk cable - fiber vs copper. I assume the cost of labor to run it is essentially the same.

The main tradeoffs I see are that you can run power over catX cable (though probably not 1km?) but single mode fiber seems to be indefinitely able to upgrade bandwidth; I'm told that old installations from the 90's are still used and are pushing 100's of gigabits with newer optics attached to them.

Like I said, I'm fairly new to this having started a job where I have to talk to datacenter people about this sort of thing, so I'm learning a bit as I go.

Optical is not expensive anymore. It's 20 bucks for 10gbps transceivers. The cable is much cheaper than twisted pair. termination will take you no longer than a network cable.

The world is not the same as it was 15 years ago :)