Ultimately it will come down to cost and afraid that is what is the driver of it.
A 100 fleet SH carrier will need circa 12 qualified pilots per aircraft on average, and assumming cost is $200k a year each that includes Salary, Taxes, training costs etc etc then that is £200-250 million dollar cost per year.
Assumming Boeing / Airbus can roll this out and I believe they can and will then their is a real benefit to airline owners.
The arguement will be passenger worries.............. well post 9/11 nobody in Europe wanted to fly on an aircraft, Ryanair introduce 1p fares and people overcome their worries very quickly for a cheap fare.
I would expect 2-3 years iof transition where Pilots are present in the cockpit but from first introduction I would expect 10 years before we have automated fleets in many countries.
Circa 2040 is probably not unrealistic.