If any one of those 5 cities decides to regulate more aggressively, it could be an immediate, material negative hit to Uber.

Pareto distributions are common in two-sided markets with geographic factors. BUT, when there's a reasonable possibility of extra regulation imposed at the regional level... that's a big risk.

Well then, the real need is to determine if Uber's competitors suffer a similar issue or not.

The last line in the article answers that pretty well:

"One thing the filing makes clear: It wouldn’t take a global movement to stress the company’s business model. A couple big-city mayors could do that all on their own. "

Their business model is unconstrained growth to funnel money into side projects. That can't persist forever. If they just stuck to their core business they could easily be profitable as taxi 2.0.

Is the net cost of these "side projects" greater than the $1.8B Uber is losing? I'm missing that in the S-1 if so.

it doesn't cost that much to pay off a mayor.

The "Government" is real cheap in Chicago.

Yeah, a children's book in every Uber.

I'm willing to bet the low hanging fruit if you're gonna bribe a mayor from that list is São Paulo.

It's not a vulnerability. It actually shows their revenue is pretty geographically diverse.

You can't trust financial news from propaganda outlets like Slate because they only care about their agenda.