Threads like this give me a headache.

Large cargo aircraft will go single pilot first.
Once a statistically significant increase in safety has been established, single pilot ops will come to passenger ops
In both cases, the automatic nature will be the primary driver and the human pilot will be the backup.

Then, when a proper infrastructure has been designed, tested, and built, unmanned cargo planes will come online.

But let's discuss the REAL reason for single pilot an zero pilot aviation operations.

Safety, right?
WRONG!!

it's money.
So when it becomes economically advantageous to kick the pilots out, it will happen.
Who to watch? Who will profit?
Google, Amazon, Boeing.

Timeframe?
It's difficult to predict. Cargo will likely happen soon, basically because no one cares if a cargo plane crashes (brutal, but true).

Skip the Sully argument. An automated system would have made it back to the airport.

Final argument:
If people willing fly in Spirit Air to save $25, they will fly on an unmanned airplane to save $25.

The whole "Normal passengers would NEVER feel safe in an unmanned airplane" argument is no match for the inherent cheapness of the average flying commuter.