I think it’s political will more than structure. The desire to play obstructionist politics has consumed parties on all sides, to the detriment of the population at large.
The appeal to extremes and gerrymandering came afterwards. The obstructionist politics are not about willpower -- the issue is systemic.
*Climate change doesn't count because one side doesn't see it as a threat.
Say you have a senator who's constituents don't care one way or the other about your bill but their party affiliation requires them to vote against your bill. You toss them an earmark that they can use to say "look at how I've helped you" to his constituents next election with the understanding that he'll break from his party's default position on your bill.
It's also obviously clear that at least one person in the US government doesn't like the current state of our infrastructure and would love to do something about it.