>slowly lose market share over decades, end up doing nothing and yet more profitable and more valuable than ever

>SpaceX

SpaceX has been gaining market share, not losing, and its primary business is Starlink, of which most customers are consumers.

(there is also Starshield)

Having used it, Starlink's entire business model seems to be rooted in handwavium. You'll almost never hit advertised speeds or latency, and there are regular outages where you get no service at all. The cost of the service fluctuates constantly if you don't get locked-in to a specific rate, too.

My impression is that Starlink is a hastily-launched DoD project. It's not a broadband replacement and scarcely an alternative to other satnet providers or LTE hotspots.