Well...copper lasts for ever....fiber has a glass core...when the freezes it contracts..when it warms up it expands...eventually that effects the way light travel through the core...eventually fiber needs to be replaced..plus you have expensive electronics on both ends...copper just carries electricity...needs cleaned once in awhile
Most provider-grade backhaul fiber products were designed to last 100 years when I worked at Nortel in 2000. Maybe earlier products had a shorter expected lifespan? The majority of the periodic expense is the equipment upgrades, just like with wireless (e.g. 4G to 5G), and repairs when a line gets cut, just like copper. I am not sure about the quality of the fiber run to my home however.
Glass really doesn't last very long...just the nature of the beast...tiny imperfections cause light to do weird things...a tiny speck of dirt can take a circuit down..if you splice a cable..you cut the core...eventually gets misalighned...
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We have two cable companies with separate hard lines on the poles (Spectrum and Grande) both offering a maximum of 940/50 while AT&T Fiber is 940/940.
i would love to have internet like that. maybe this summer 
The old pots equipment has been retired in the central office...so everyone on fiber is actually VoIP
After consulting with a friend who works in one of Verizon's test lab, he says: "we plan on having to replace residential fiber lines every 50 years, but expect them to last much longer in practice. Long distance fiber lines are designed to last even longer. It doesn't mean some cables won't fail before that. There is a statistical distribution just like anything, but the MTBF is looking favorable compared to manufacturer specs so far."The Lifetime of Fiber Optic Cable
In general, people building networks are working on 40 years as a minimum, and some are expecting it to last 100 years. But some people think that fibre lasts only a couple of decades. Fiber optic …
Thats in a lab...no car accidents taking down poles...the laser will fail long before the fiber needs to be replaced....but here is the real kicker..as lasers get better...they will need different fiber...the people you are talking to are the ones who came up with the 5g self install kit that worked great in a lab but failed miserably in the field...the 5g frequencies were too weak to penetrate walls...verizon bought a bunch of c-band frequencies to replace and suplement the original uhf frequencies...not 5g national..the ultra high speed 5g
Isn't the the same with copper. If a pole gets hit the wires need to be replaced. Most of the infrastructure is above ground no matter what it is.
Copper carries electricity..doesnt care if a wire gets bent...light bounces down the core of a fiber...you bend it too far it creates a blemish in the core..might cause the light to bounce a different way and screw up the signal...light is a much cleaner signal than electricity as far as static and interference but of the path of the light gets disrupted you get jitter and bend loss which weaken the signal that can cause all kinds of issues by screwing up the data transmission...you could get macroblocking and synch issues. Etc etc etc
Nope...for fiber to the home is just one long fiber from the central office to the house...network backbones would have redundancy ...
