America's infrastructure, and the San Bruno gas explosion

A few months ago, James Fallows had a lengthy piece on the mess that America is in, and he noted:

“Engineers don’t usually put things dramatically, but the alarm about infrastructure is real,” Stephen Flynn, of the Center for National Policy, told me. “Our forebears invested billions in these systems when they were relatively much poorer than we are. We won’t even pay to maintain them for our own use, let alone have anything to pass to our grandchildren.”

The explosion in California that was heard around the world fits this description as well; the pipeline was old

PG&E officials left key questions unanswered Friday about Thursday's explosion of a 30-inch, steel transmission pipe, including how company crews responded to earlier reports of a gas leak and when the 54-year-old pipeline was last inspected.

Whether it is private or public, the roads and pipes and airports and most mundane things that add up to the term "infrastructure" are rapidly getting old, and we seem to be spending fewer and fewer dollars on maintaining them, leave alone building anew.

A contrast to this is the pace at which we seem to buy new gadgets--from iPhones and iPads to Kindles to ...

Could this be because "infrastructure" is collectively consumed whereas the gadgets are for private, individual usage?

In that case, we are back again to the fundamental issue of "public good" versus "private good" in economics.  When the roads and dams and bridges were built in the 1940s and 1950s, how come we had that much more money to spend on those collectively consumed public goods, and how come we don't have a dime to spare?