Quoting c5Load (Thread starter) "Surely, they don't go straight from the simulator to an actual revenue flight with pax and all do they?"
As previously stated, "Yes, they do."
These days, the quality of simulators (Level C and Level D) are such that they are certified by the FAA to fully qualify pilots to fly the aircraft.
When I got hired by an air carrier, the training program was something like (I don't recall exactly): one week of company indoctrination (finance, scheduling, bidding, general expectations, CRM training, etc.), two weeks of aircraft systems culminating in a 100 question written examination, two weeks of procedural training (running checklists and referencing proper procedures during normal and abnormal operations--this was accomplished in a non-motion simulator) and two weeks of full motion simulators (approximately 10 sim sessions, each one 4 hours long. Two of the ten sessions were evaluations, the other eight were instructional. It was something like four sim sessions and a progress evaluation; then four more sim sessions and a final evaluation).
When I was hired, I had about two thousand hours of flight time, but none of it in the type of airplane I was assigned to fly at the airline.
The very first time I actually flew the airplane and made a takeoff and landing, it was a regularly scheduled passenger flight with about 100 passengers on board. I flew two trips (a four day trip, a few days off; then a three day trip) with two instructor captains (as mentioned above--Initial Operating Experience IOE totaled a minimum of 25 hours) then I was released to the line to fly with any assigned Captain.
From the day I walked into training until my first flight was 45 days (and of course, there were two days off each week. It was not 45 days of training without a break!)
It was quite an amazing process.