From an infrastructure improvement point of few, state funded fiber beats all other uses of infrastructure tax dollars (I've been doing research as part of my 'Sunnyvale Fiber' project). At the state level, legislative support for a 'digital' easement allows for emminent domain type land offset cases (where the state comes in and says "for this parcel we're going to require an underground easement for fiber transit". The good news is that you can (if you choose to) bury these things 50+ feet down which protects them from most threats. Horizontal drilling capacity (some sitting idle in fracking fields) can be employed to create the necessary conduit for generally long lengths (up to nearly 5 miles or 25,000' by some estimates)

Adding water, power, freeways, and airports all cost more, and generate fewer net commercial opportunities.

For one thing, cable TV companies (who are the only practical ISP in many areas) don't want competition and have no reason to do it themselves.

It is worse than that. Of course they don't want competition but the the monopoly services areas are an artifact of legislative deal making. So the current situation is codified in law and would need to be changed.

Monopoly service areas for universal service offering was the deal.

This is a huge barrier, there is a lot of 'rent' money being doled out to 'sole providers'

They're not going to exist in every locality. My relatives are still on satellite and dial up.