It's hardly surprising that people without the money for cars are of the opinion they aren't so important anyway. Not being able to afford things tends to draw into sharp relief the difference between wants and needs.
And I realize Ford's marketing department can't do much about the slow, grinding recovery and thus are stuck worrying about long-term attitude shifts. But until the demographics show millenials moving to and staying in urban areas where transit is a feasible option, I can't imagine it's legitimately worth fretting over.
If millenials still choose to settle down to raise children in the suburbs, car ownership is pretty much necessary.
The only real threat from lasting attitude change, is that perhaps millenials will vote for more transit projects and subsidies over more car/road projects and subsidies and thus make it more feasible in more areas to not own cars.