Everything comes instead of something else. Whatever effort and resources are spent adding gigabit to new homes will mean fewer homes, less food, shoes, medicine, natural gas, cars or whatever.
Many people will be celebrating faster internet speeds for those who purchase these new homes, but it's hard to see what goes missing when it's a little here and there from across the economy.
Not everything is zero-sum.
Sure, it takes effort to wire up every home for Gigabit, but on the other hand you're employing more telco workers to run the cables, creating more jobs. Gigabit costs more, but economy of scale means that average prices will be lower. Increased bandwidth opens up space for new technology innovation, and letting more people effectively work remotely (so less cars on the road).
In practice, from what I've seen in the US, I'd guess this work was probably going to happen anyway. AT&T has been busy running fiber-to-the-home for every major neighborhood in the bay area. (I've gotten 10x the bandwidth, for roughly half the price I was paying for DOCSIS cable internet before.) It wouldn't surprise me if telcos in Europe are on a similar roadmap.
Once the neighborhood fiber line in place on the poles, running a line to an individual house has negligible cost - especially if it's new construction and you're already pulling copper for power/telephone/TV. It took AT&T 30 minutes to do it at my last two houses.
I didn't say it was zero sum - in fact it's definitely NOT zero sum. Adding gigabit to new homes will certainly - almost tautologically - come instead of something else.
The question is whether it's worth what you give up or not. Maybe it is, and maybe it's not. But it's hard to make the correct judgement when you focus only on the gains of the gigabit, but it's very hard to count all the things you DON'T do instead. There's no great solution to this, but we must at the very least be aware that we are giving up other things that we might also want.
As far as "creating jobs" - People are already working hard. "Creating a job" in one area really means (implicitly) re-purposing someone from a different activity of different value. This may or may not be a net win. The person could have been cutting hair, doing accounting, playing football, or simply running a fiber cable in a different area of town - but they aren't, they are running this cable right here where we "created a job."
I'm honestly surprised to see this kind of narrow thinking on HN.
Ideally gigabit internet will come "instead of" a few extra pounds of profit in the pockets of the builders. More likely, gigabit internet will come "instead of" a few extra pounds remaining in the pockets of the home-buyers. It's also possible that this will just prompt companies already installing equipment for new neighborhoods to install the reasonable piece of kit, rather than the cheapest piece of kit possible, at an added extra expense of nearly zero.
Sometimes the "economic" decision right now is just punting significantly higher cost of rework down the road.