I was actually wondering what bit of infrastructure would be the legacy of the late 20th and early 21st Centuries. Free connectivity on the internet would be almost as impressive as properly maintaining the hard infrastructure that our parents built in the mid 20th.
we both know 'free' is a subjective term
There is a model for this...toll roads like Massachusetts does with Bridges, Tunnels and it's Turnpike.
Semi-public/semi-private, whatever we call it, works well. There are problems with this sure, but it seems to work out very well compared to other choices.
There are other areas where this public/private partnership works miracles...the government funds research and development in the USA.