Their business model works. That's why they're bigger than GM now. And that's why suddenly they're being perceived as unfair and exploitative.
In the Western social democratic system that more or less pervades the old industrial nations of Western Europe and the U.S., financial success is an invitation to lawsuits, unionization, and government fines.
The unionization is couched as a class warfare thing -- the management/owners are making big bucks and we workers are making peanuts -- but in reality, it's all about fighting for a piece of the pie.
The Teamsters rep in Oakland summed it all up: even though Uber's buying a big building there and employing 2,000 to 3,000 people, it's time to unionize and make them "give back".
I just hope that Seattle and California don't set a national trend, or this may be the beginning of the end for the sharing economy, just as manufacturing ended, and just as outsourcing has hollowed out the computer programming field and other domestic professions. What will there be left for Americans to do, if we keep shooting down every innovative business model like this?