Oh god, back to the pilot & dog / pilot-less aircraft pipe dream.
Where do I start? Just a few random thoughts, but not limited too:
Lawyers
No manufacturer's lawyer is ever going to sign-off on the pilot-less aircraft, the reason for the simple reason of responsibility. It would all fall on the manufacturer. There would be no dead pilot to blame.
Engineers
The pilot-less aircraft is the engineering wet dream, engineering out the pilot is all about ego, not cost saving. Can it be done with the 99.999+% reliability that we have today at an acceptable cost?
Infrastructure
Think about the infrastructure that needs to be installed in just terms of communications. An ultra high reliability two-way data link with a robust signalling protocol & guaranteed message delivery. There would also have to be a continuously revised failsafe flightplan/groundplan on the assumption that the data link could fail at any point in the flight.
The sheer cost & time to develop this would be enormous. It however, can be done.
Every single major aerodrome would need to be fitted out with every component of such a system before it could be used as a "automated destination". So what would operators do in the transition period? They would still have to have crew aircraft fitted with a conventional flight deck AND the fully autonomous equipment for city pairs that weren't "fully automated". Increase costs for long term gain, this is not how capitalism works.
There would only ever be one smoking hole in the ground from pilot-less RPT aircraft, public confidence would be shattered by a single fatal accident.
Dog & Pilot show
There is a very good reason why all FMC entries are cross checked by a second crew member. I have lost count of the number of incorrect entries that have made & been picked up the other crew member PRIOR to execution.
Once again, the first fatal "single pilot" accident would put an end to such a practice.
Pilots & ATC provide a very flexible adaptable system. Automation, being rule based is the opposite of adaptable. Bean counters focus on costs incurred, rather than costs saved through this system adaptability. A less adaptable system would in all likelihood increase costs that dwarves those of having two pilots at the controls.
In short we won't have a dog & pilot show or a pilot-less RPT aircraft any time soon. There is not even the faintest mention from the industry for the next generation A350/B737 replacement. With the current development cycle a timeline in excess of 30 years would be the earliest before such a technology could be deployed, notwithstanding my reasoning.