The discussion's been ongoing for years. Obama spent a good bit of his campaign and first term pushing an "infrastructure bank," and eventually just started asking for increased spending, over and over. The lack of progress stems for Republicans in Congress rejecting those efforts because they didn't want the Obama administration and the Dems calling for increased spending to get any credit for it.
Here's one of many examples, related to an Obama/Sanders proposal killed by the GOP Senate.
This bad faith obstruction during the Obama years- and voters' decision to reward that bad faith obstruction by electing Republicans in 2014 and 2016- puts the Dem in a bind now. If they work with Trump they not only boost his reelection efforts but also reward the GOP obstruction strategy with exactly the outcome they sought, thus encouraging more obstruction next time there's a Dem in the White House. If they don't, obviously there's no new infrastructure funding plus the norm-breaking Trump will blame it all on them and the press will dutifully report his angry rants without the necessary context.