Can someone ELI5 Starlink revenue sources? At the core, it's an ISP (but served from space). What does Starlink have that differentiates from any other ISP? Is it because the TAM is global? That may be true at the margin, but I am sure most eligible subscribers would prefer a land-based system (eg no one in SF is cancelling their Xfinity to use Starlink) so how much is really left for them?
It's because they're good speeds in a lot of places that couldn't get good speeds before. It's also great for mobile work sites, i.e. construction sites, drilling camps, other b2b service businesses where a bunch of portacoms rock up to a site. Anywhere it's mildly hilly you can't actually assume you'll get a signal outside of town but a satellite dish basically guarantees that. Even if you can guarantee your in a spot long term the upfront cost of fibre or a tower may not balance out as cheaper than just eating the higher bandwidth costs.
It's also worth remembering that in a lot of places with low density it isn't appealing for competitors to build out to, so there's a lot of markets where it's a no brainer to switch from the local monopoly to starlink because the price was already inflated and it was worse service.