mutt...
Not 'different in the USA', just not necessary, many skilled applicants for jobs available.
Have personally trained pilots with (approximately) 250 hours total flying experience as First Officers in heavy jet transports.
They required, on average, in addition to normal systems ground training, 35-40 hours sim training, base training (sometimes as many as 30+ circuits), 200 hours of concentrated line instruction before being released to normal line flying, and THEN only scheculed with experienced Captains (in type) for the next 100+ hours. After ninety days, another line check to be sure they are operating to standard.
About half of the guys I trained were on the B707, a much more difficult aeroplane to fly (accrutely) than some of the more modern jet transports.
Many airlines simply do not have the resources to commit to this type of very expensive training...and IF guys are available that HAVE the required experience, then they are selected.
Just the way it is....good or bad, depending on your outlook.