>nobody was held liable and in fact no charges were pressed and no civil lawsuits were filed
As noted below Uber settled (that typically means their insurer settled) so there is no need for a civil lawsuit. That is efficiency of the system and how the system is supposed to work. In other words you only bring a suit against the insured if the insurer wrongfully denies your claim, here the insurer paid up, so there is no need for a civil suit by the estate of the deceased against Uber.
The criminal side of things is interesting...but for sake of argument lets say you were in an accident, further assume it was your fault, resulting in a fatality. Typically, unless there was a separate crime (e.g. DUI, drag racing, etc...) there will be no criminal charge, just a civil traffic ticket for the accident (in many jurisdictions there will be a specific charge/penalties for an accident resulting in a fatality, but that will still be a traffic ticket, meaning non-criminal).
I am curious if the "driver" received a traffic ticket for the accident, my guess is he did, I can't imagine the responding officer(s) not issuing a traffic ticket for an accident much less one resulting in a fatality. Interestingly these traffic tickets for accidents with fatalities do usually carry a potential penalties that include suspension of the drivers license, so I do think the law will need to catch up with reality in that regard because suspending the driver's DL doesn't seem to punish the right party in the case of a self-driving car, so perhaps these states that allow self-driving cars need to think about adopting traffic laws specific to self-driving cars and figure out who those tickets should go to and the proper punishment (obviously you can't suspend the DL of a self-driving car or a car company).