Who stopped building highways? In the Dallas area we've been building and expanding them non-stop for decades now. My experience is people have simply moved further out, increasing traffic flowing into the newly expanded/built roads, and overall congestion has remained constant.
But I think many of us would agree about accomplishing Big Things. Here's the dirty little secret: the US Government has almost always funded those "Big Things" and taxed the rich heavily to do it. The Interstate highway system was funded by a massive (as a percentage of the price per gallon) gas tax, along with a 90% post-war income tax rate on the rich.
Even the trans-continental railroad was funded thanks to guarantees, loans, etc from the US Federal government (including sending the Army out shoot Native Americans and bandits who attacked the railroads). No private entity was willing to take such a large risk - it could have bankrupted even JP Morgan if it went bad. Without "Big Government" support the line never would have been built.
I'm all for bringing back much higher taxes on the rich - tax anything over $1 million income at 50%, over $10 million at 60%. Same for cap gains. Use that money to fund massive expansions of roads, build subways under every major city, heck start a government-funded bank that gives anyone who wants to start a business a loan (it's what the Chinese government does).
We could do a ton of "Big Things" if we were willing to tax the uber-rich to pay for it.