As I see it, the moat for terrestrial (and in particular wire-based) last-mile comms infrastructure is that each additional customer connected is often expensive, and if they switch to your competition, that wire is basically a sunk investment.

For wireless, the dynamics are very different (as long as spectrum isn't monopolized). As soon as you have enough satellites launched for global coverage, you can compete for all customers, and each one that switches away to the competition is more bandwidth available to you to undercut your competitor on pricing with.