- For a lot of public utilities, the point is that building several parallel sets of infrastructure would be really wasteful. It makes sense to build it once, hopefully well, and let everyone use it.
- One might think this only is true of strictly terrestrial infrastructure like phone landlines or water districts. But of course, GPS is an example where we all benefit from a satellite constellation which is operated by the US military with an annual budget of roughly $1B -- and we can all use it for free. Had the US not provided for civilian access to GPS, and instead there were several competing private systems, they would all be worse and every application which is today based on GPS would have an additional monthly fee to access whichever private constellation that application had built around.
Admittedly, satellite connectivity comes with a bunch of complexities that GPS don't have. But still, if we were smart, would we be building one giant common-access constellation rather than multiple competing ones?