I think it might be comparable.

It's really hard to estimate since we don't know their satellite costs, but $100 million per satellite (launched) is probably a good starting point. That ends up being $13k capital cost per customer. If they can borrow capital at 5% or less, that works out to ~$55/month.

But if they succeed with reusable rockets (and it sure looks like they will), they can probably drop the launch cost from $60m to $10m in the near term. If we assume the satellite still costs $40m, that still cuts the total cost in half to ~$27/month @ 5%. Maybe they can mass produce these satellites and get them to $10-20m each, which would reduce it to more like $15/month.

Again all these numbers are pretty rough/best case scenarios, but even if we multiply them by 10 we could be looking at 1 gbps connections for $150-500/month. That could be cheaper than fiber infrastructure in a lot of places and still immensely useful in applications where fiber isn't possible (in a car, plane, or boat). That's also assuming 1 TB/customer. In many cases you may just buy the bandwidth in smaller increments at $1-10/gigabyte which is a few orders of magnitude cheaper than current satellite internet and comparable with LTE cell coverage.

They're only going for 51 orbital planes and it's fairly simple to spread out many satellites from a single launch if they're in the same orbital plane. And a Falcon 9 can carry 20,000 kg to orbit whereas each satellite is pretty light. Some people on /r/spacex calculated that the binding constraint is actually the volume of the Falcon 9 payload fairing and they'll be able to launch 20-25 satellites at a go. And I would expect that mass produced satellites to be far cheaper on the margin than bespoke ones. All of which is to say that it's probably more like $10 million per satellite launched.

In cities, the fiber, or even some form of local wireless, is much cheaper. However, in more rural areas the satellite system can well end up the cheaper choice.

The interesting part is what building 4425 satellites does to the economics of making satellites. Right now, most satellites are one-offs, or at most made in a series of 10 or so, handmade to exact specifications for maximum reliability and built for 25+ year lifetimes. This fleet is meant to be mass-produced and built to last a much shorter time, 5-10 years at most. I am very interested in just how low can they drive the cost of making a single satellite.

"This fleet is meant to be mass-produced and built to last a much shorter time, 5-10 years at most. I am very interested in just how low can they drive the cost of making a single satellite."

One of the best points in the discussion. This has potential to produce side-effects more valuable than whatever they were attempting to do. As in, they can fail in their overall goal but a ton of great things would come from success in this part.

Interesting when you say "However, in more rural areas the satellite system can well end up the cheaper choice."

You mean a satellite system can well end up your ONLY choice. If you're rural there are no choices besides dial up and satellite. Satellite is a reseller selling hughesnet.

So long as it breaks even, SpaceX comes out ahead, since they're deploying the sats, and learning how to build the sats in a mass produced way.

+ economies of launch scale.

It depends on how far apart those 6 million people are and how much infrastructure is already in place.

Since satellites handle most worst-case distance scenarios with respect to fiber, it is reasonable to assume a connection spanning the world (including access to remote areas)

Depends where those 6 million people live. I've heard internet in Kilimanjaro is not that great...

So they'll be able to get awesome bandwidth (by today's standards, anyway), but the monthly plan is might be a little pricey.

Pretty much yes. It's not about giving $30/month broadband to remote parts of the globe...