At that point, Uber pulled out the brakes and that changed their view on regulations permanently.
Source---straight from Travis (TK) himself.
The question around Uber was whether the laws would be changed to make them a taxi, which after much lobbying they weren't, but they were already fine under the existing laws. As kenbaylor says below, Uber themselves thought the laws would quickly be changed to make their business illegal, so they didn't even get into that market until Lyft forced them to do so.
The difference is that Uber was not created to fleece the masses via investment pump and dump scheme.
As of now, ICOs are purely pump and dump. They are modern day unregistered securities, promoted via modern day version of faxes
taxi drivers are selling their medallions that they used to offer service. They are selling these medallions at a loss because a competitor is eating their lunch.
I'm still not sure exactly why this didn't happen, but if people can agree that Uber isn't a Taxi, then I think they can also come to the conclusion that an ICO token isn't a traditional security... the world just isn't as black-and-white as we often like to think, and legislators are human beings that have a lot more flexibility around enforcement than people imagine.