Additionally, there should be about 150-200 satellites above the US in the initial deployment.
They also plan to upgrade the satellites themselves (according to SpaceX's Mueller) so they're much larger. That should, in principle, allow them to exceed the per-satellite throughput of GSO birds like Viasat's which are over 1Tbps per bird.
They aren't competing with fiber in Denver. They're competing with high-latency and expensive satellite internet in rural areas. It's possible they may eventually dip into the cities a bit if they sell out their capacity and then build out their VLEO constellation (total of 12,000 or so satellites, but in much lower orbits enabling yet lower latency and higher bandwidth).
But Iridium's problem wasn't a lack of capacity, it was slow customer acquisition combined with very high interest rates and launch prices. If SpaceX fills up their network with customers to its capacity, they will be just fine.
For rural areas, there are wireless ISPs for rural areas here in Colorado where you put an antenna on your roof. You get line of sight to an antenna on a nearby mountain for internet service. I don't see how Starlink can possibly compete with that on a technological or cost basis. It seems like most of the western US could have service like this for many rural markets, if it's not already available.
So I definitely think Starlink could compete in that market. But more as an equal than as the only option.
If SpaceX is going to make huge returns on starlink, they will have to be price competitive with at least the DSL providers that are in many rural communities. Many of your remote rural areas in the US have at least 6 to 10mbps for ~$60 a month, and that's plenty for most casual users. Even for video streaming.
And that's now, when there's still large urban areas in a lot of countries on DSL. Once that DSL is phased out, rural areas are going to need better sattelite options or expensive long stretches of fibre to not fall behind the curve.
The main issue for rural satellite access is no longer bandwidth or even data caps but latency.
And if you have DSL in rural areas, count yourself lucky.
What about mobile users?
Starlink doesn't work for mobile users, either.
Essentially seeding their own demand in a market that didn't previously exist (cheaper launch on reused rockets).
As a side benefit, they get the ability to put a constellation in orbit (and continue adding to it) at a fraction of the cost of their telecom competitors.
Therefore, if Starlink suffers the same fate as Iridium (but without damaging the rest of SpaceX), that would actually be a big net win. Iridium emerged from bankruptcy, turned a profit and launched replacement satellites and is now in the process of a huge constellation refresh, using SpaceX's reusable rockets. If that happens with Starlink, that would be a complete success for creating launch demand.
I choose where to live because I can have two different fiber connections (for speed and a failsafe). How long will it be before satellite internet offers 2gbps symmetrical with low latency at reasonable prices?
I can hardly imagine a situation where internet access is so critical at a home that you need two fiber lines anyway. I have probably had 2 hours of downtime in the past 3 years with my cable connection.
That’d put SpaceX in league with other telecommunications giants.
That’s, of course, not the only possible outcome, but that’s why the valuation is so high.