Drones are coming, just not to replace pilot jobs any time soon.
Right now the big hurdle is FAA certification to operate in non-restricted airspace below 18K due to the see and avoid rules. The technology is there to certify drones with sensors that will enable them to maneuver around the VFR types down low. This will happen eventually.
Even after drones are flying with the rest of us in the U.S. airspace system, the current batch have little to no weather capability. No de-icing, low crosswind limits etc. FedEx and UPS (and pax airlines) need a product that can deliver the mail/people quickly, reliably, in bulk, and in marginal weather.
The Global Hawk cost $35 Million and up. To make drones economically viable you’d have to redesign them ($$$) to be able to perform as well or better than airliners AND at a cheaper implementation cost. You could retrofit a Boeing to fly remotely but it would still be expensive to do so and the liability issues if something goes wrong are huge driving up costs even more.
With all the technological, financial, and development issues I wouldn’t be surprised if drones never replace the batch of airline and cargo planes flying today. However I do think we will see large numbers fulfilling a role in law enforcement and surveillance roles. These are the missions that drones make financial and operational sense and exactly the types of missions they are doing today. It’s interesting to note that drones still require experienced pilots for launch & recovery and their mishap rate is vastly higher than manned aircraft.
Just because the technology is capable doesn’t mean it makes economic sense to implement on a large scale.