When infrastructure is built, it usually starts out as a large scale project that can only be accomplished by government. It can be built in undeveloped areas for a fairly large amount of money, or in developed areas with massive amounts of cash and even more political capital. That's hard to do in democracies, though seems to work well in places like China.
This dynamic means that we'd expect infrastructure to fail over time as the inertia arrayed against repairs and new construction grows. That seems to be what's happening in the US.
When infrastructure decays and fails, though, it creates a lot of opportunities. Citizens who were meant to be served by the infrastructure become unhappy and are when that unhappiness is great enough, they will spend their own dollars on alternatives. This is a more direct process than funding infrastructure through tax dollars, though it can produce different types of outcomes.
In the United States today, these opportunities are being exploited by a range of startups and companies who are essentially building private infrastructure, mainly for the relatively wealthy.
Instacart is building new infrastructure to deliver food to homes. In most early use cases, this looks like pure convenience, however, over the long run it could impact and start to eliminate food deserts. By making food available in more places, Instacart has the power to change where people want to live. That process will reshape how cities grow and, eventually, are built. I'll also say that in a place like NY, where supermarkets are small, crowded, and overpriced, it seems clear that the current system only exists because there's no better alternative. Instacart is that alternative.
This process is also starting to play out on our roads. Most of our highway system was created by a single gigantic bill, the Federal Aid Highway Act of 1956. It would be hard to imagine today’s Federal government getting its act together or finding enough money to repair roads on a national scale. Harder still would be believing that a place like the Bay Area would figure out a way to install effective and efficient public transportation to ease the stress on our roads and highways which are nearly always gridlocked. Technology is starting to provide ways to bypass those problems by improving throughput on existing systems without changing the physical plant.
Self driving cars are the most extreme example of this trend. If we do actually arrive in a world where self driving cars are ubiquitous and built on the same standard such that they can communicate with one another at long range, congestion gridlock should largely vanish as the cars plan miles ahead and subtly change speeds to clear up slow downs before they start. Even before that future, though, apps like Waze help drivers plan better routes and alleviate some stress on the most crowded points in the system.
I think the trend is also impacting power generation and consumption in the US. Companies such as Solar City will install your own power plant on your roof which means you're no longer subject to brownouts or price increases at peak times. In most of the US, this is more of a ‘nice to have’ and cost saving measure, but in the third world, solar power could provide a viable and efficient alternative to the construction of large power plants and electric delivery systems. These systems would be a fraction of the price of the old way of doing things and be significantly more reliable thanks to their distributed architecture.
Private can’t mean wealthy
There is, however, an underlying tension in the rise of this new infrastructure in that the first segments of the population to get it are generally the wealthier ones who can afford to use it. Two tiered systems may be fine when they exist in non-essential parts of our lives. However, when there are two tiers, determined by wealth, for services as basic as energy, we're in a dangerous place.
That's part of why infrastructure exists the way it does. No single piece of the population would spend enough money to build services and systems useful for everyone. I think that's always going to be true for certain projects, such as bridges. But, as technology drops the cost of delivering the types of services we traditionally associate with infrastructure, I think we'll see the market extend its reach farther and farther. There's a huge amount of money to be made by ensuring universal coverage, but it won't be easy to unlock all of it.
 At best, though, this is a partial solution. Throughput is well and good, but if the roads actually start to collapse, we'll need other solutions.
 Even though this seems like a good idea, there are still quite a few hurdles, not the least of which would be figuring out the right financing structure to make the installations profitable for the companies doing them. This is harder than it might seem for developing countries without sufficiently developed/ubiquitous banking systems.