On the other hand, roughly 85% of the population worldwide is already covered by 3G or 4G networks. I am not sure that space will be able to offer lower prices for backhaul if the infrastructure is already there. A fiber PoP / tower has much lower OPEX than launching, operating a constellation of satellites.

First, and less importantly, source. Because phone companies love to toss out coverage numbers that are pure, unadulterated bullshit. But second that's less important because 3G and 4G are both completely uncompetitive for broadband. LTE is basically the minimum there. And awful data caps and congestion remain a serious issue all over the place.

>A fiber PoP / tower has much lower OPEX than launching, operating a constellation of satellites.

Is it? I mean, seriously. A lot of SpaceX's plans are based on estimated launch costs via Super Heavy, so necessarily somewhat speculative. But the target is sub-$100/kg, and at least in terms of fundamentals (like cost of fuel, Raptor effectiveness, estimated cadence) that doesn't look ridiculous. Each Starlink satellite apparently has a mass over around 230 kg. Add a bit of extra mass for some bigger sats in the mix, double the launch cost to be a bit more conservative, and we're still talking a launch cost per satellite of well under $60k a piece. They necessarily have everything needed to operate their design lifetime, because there is no maintenance that can be done on them. They're operating low enough that solar weather shouldn't be too constant a concern, and of course will never face OPEX costs like vegetation clearing or weather damage or corrosion or the like. Also doesn't face NIMBY tower politics either. Is it actually more expensive then running fiber and building/maintaining a tower? For very high density locations probably, but there's a pretty sizable population in the US alone for whom it seems on napkin math it could be very competitive.

Regarding the costs, I am not sure where your 60k/sat is coming form. Currently, launch costs for SpaceX are in the millions (60 commercially, let's say 30 millions cost), and they are launching 60 satellites at a time, so at least 500k/sat.

I am not sure that they will be able to cut the launch costs by a factor of 10, even considering resusability, larger launch capacity, etc, etc.

[1] https://www.gsma.com/mobilefordevelopment/wp-content/uploads...

In the first Starlink launch, with 60 satellites of ~230 kg each, the cost of launch was ~$30M (considering that the "retail price" of a Falcon 9 launch is $60M, I guess that half the cost if a good assumption). Thus, the cost per kg was $30M / (60 * 230 kg) ~ $2,000/kg. I just don't see how they are going to achieve a x10 reduction in cost, even considering reusability, larger masses, etc, etc.

For cities, you're right - 5G + high frequency wavelengths is probably cheaper - but not by that much assuming SpaceX's numbers are accurate.

The problem is 85% of the population is absolutely not covered by high frequency spectrum - tower/DAS coverage is optimized for sub 1Ghz bands. We would need billions upon billions of additional tower builds to deliver an adequate experience on spectrum that basically requires line of sight. Even in cities. Some of that has been invested already (e.g. VZ can reuse their Fios plant in many locations), but certainly not everywhere.

Satellites may very well be more cost effective.

Consider the reverse.

As internet access becomes a staple service for modern living, one’s options for location are restricted to where internet is available: 3G coverage at a barely functional minimum.

Want to solve the housing crisis? poverty? Bring at least LTE performance (100Mbs better) everywhere at a competitive flat rate. Today, many options are untenable for want of a decent data rate.