As interest in car ownership drops as the Millennials age and take the older generations' place, that problem may fix itself.
What do you mean by interest in car ownership?
While this article[0] demonstrates that numbers have improved slightly for actual car ownership as millenials age, it still contains other tidbits and statistics (like the having driver's license by 18 stat at 60% vs. 80% in 1980) that reflect views on car ownership amongst millenials today.
Anecdote, I don't have a lot of mileage (pun unintended), but every girl I've ever dated did not have license, and neither do I, and I am 27. I live alone and bike and bus ride for the most part.
[0] http://www.latimes.com/business/autos/la-fi-hy-millennials-c...
Don't make the mistake of making macro predictions based on a niche segment. I think generally people aren't "interested" in car ownership; they are interested in fulfilling their transportation needs as best as possible. Car ownership just happens to fulfill that the best right now.
There is the possibility of increased urbanization and improvements to self-driving car technology will make it economically feasible for car ownership to be unnecessary for most, but I highly doubt that happens within the millennial generation. Probably the next one.
Because people have opinions on trains. So instead of building train tunnels you debate it for 20 years in town halls and NIMBY protests and nothing changes.
This is clearly a hack around that issue. The article mentions a Hyperloop several times, that's the ultimate goal here.