What's interesting is that through greasing the wheels of the economy via infrastructure investments (e.g. better broadband, connected/wired roadways, upgraded utilities and transportation hubs) you would see productivity gains which, over time, would further diminish the value of labor.
Have always been interested in how long-term goals of social/economic policy should influence short-term decision making, but there aren't any easy answers.
Calling it '4 trillion' is technically correct but I find that taking out the passthru social programs (SS, medicare, medicaid) leaves you with the real number of what's available to allocate differently. Hard to say that we could pay for something out of SS benefits while still collecting FICA tax, and if you want to eliminate the program entirely that's a different discussion.
Bring that schedule forward through issuing more debt at record-low interest rates, and bang, you've solved several problems at once. People have jobs, they spend money, that helps the economy, and we get the infrastructure out of it as well.
You'll even get some of that inflation that's been missing during the QE period, while all the fed economists looked at their macro textbooks in utter confusion.