. However, there's nothing to stop competent captains from allowing the F/O to "drive" these 'frames on straight stretches of taxiway with shallow turns to give them confidence, so that in the event of landing with a dead captain they could at least steer the beast off onto the highspeed exit (where supplied) and save the airport operator the hassle of a blocked runway.
Most co-pilots with a Major Airline probably have tons of experience and have flown left seat and taxied airplanes for years before they got stuck in the right seat.
(I had 12,000 hours and previous commands of kites from DC-3s to B-747s before AA hired me. Same with most if not all the pilots in my class, lots of time and types)