Cancer research is only one example, a new road also requires a minimum amount of money. Many people would happily pay for their chunk of a new road/bridge if it made the difference between having it and not because the cost is less than the utility. But, you don’t see charities to build roads because that model does not work in that context.

As to efficiency that’s not really relevant. What I pay to see a movie is divorced from what it takes to make the movie. All I care about is the utility.

If taxes didn't fund roads, businesses would fund them to transport their stuff around. Since an empty road is wasteful, they would also likely be toll/subscription/customers-only based for whoever else. So you would need to pay if you wanted to use the road. Now if a bunch of people want to donate a road to the world (like open source, it would happen), that is great too.

That’s a theory, but in practice that’s not what you see happen. Companies build a lot of really bad roads when they need them to get from A - B for example logging.

But, individual roads fit into a larger context. If you want to get from A to B and there is a road from A to C and from C to B then the utility is limited to time saved. Companies rarely build such roads and it’s even rarer to see them turned into public toll roads.

The US interstate highway system for example provides minimal individual benefit over existing roads, but massive collective benefit. Worldwide you don’t see companies building such things even when the demand is there.

>"That’s a theory, but in practice that’s not what you see happen. Companies build a lot of really bad roads when they need them to get from A - B for example logging. [...] Companies rarely build such roads and it’s even rarer to see them turned into public toll roads. [...] The US interstate highway system"

Why would companies be building roads like that when there is no need to do it?

>"Worldwide you don’t see companies building such things even when the demand is there."

This would be interesting to look at, where is there demand for roads?

> Why would companies be building roads like that when there is no need to do it?

Need is a poor way of looking at investments. Having a more direct route reduces travel costs. Which is while people use Toll Road‘s even when their are generally other options.

If you want to make the suggestion that companies will make toll roads you need to explain why the don’t even when their are many profitable bridges etc. Toll bridges could be profitable in many places yet they are not built largely becase the cost is so extreme.

I meant that in the US everyone expects the government will provide roads, and there are already many good roads to use for free (eg the Interstate Highway system).

As a result, people are not willing to pay much for more roads, so they aren't going to be built. It may not even be legally possible in many cases under current regulations.

Being US specific is not meaningful when it does not occur in any country.