Uber, Lyft and the challenge of transportation startup profits

How much does transportation cost you?

In most cities, bus or subway fare might set you back $3 or so. A tank of gas, maybe $30 or $40 depending on your car. An hour of street parking? Sometimes it's free, sometimes it's a few bucks. And you can usually snag an economy seat on a round-trip U.S. domestic flight for less than $300.

These numbers probably ring true for most people. There's just one problem: Everything you know about the cost of transportation is wrong.

Despite a massive infusion of venture capital into the transportation sector over the past few years, mobility startups are starting to learn what every transportation business has known for generations: transportation profits are elusive, and the system is mainly held together by subsidies. Will this be the first generation of transportation businesses to escape history?