I agree that humans may always desire some degree of FTF interaction, but I think "virtual" online edu may improve in quality to the point that it is "virtually" indistinguishable from traditional face-to-face interaction.  

Furthermore, if we REALLY want to reduce traffic--unlike rail, and at FAR less cost than rail--we could offer generous incentives to students to increase use of ever-improving online edu options, while doing the same to dramatically increase the number of workers-- many of whom can already do all or part of their jobs online--to "telecommute" from home and/or more decentralized satellite offices.
  
And if we hope to guarantee at least two years of higher edu for all--and do so "tuition free", or at least "debt free"--I think the only way this will be affordable may be to increase the number of students who use online options.  Thinking this will be affordable if everyone attends traditional "bricks and mortar" institutions of higher edu is wishful thinking IMO.