Is this because, they don't offer or FO's don't make it? How the training is compare to US major Airlines, is it more difficult or is the same?
Both. generally, if you have a good record, they will offer you a command at the 8-10 year point but again only if you haven't had problems on any of your several checks. If you want an early command, IE Freighter Capt., then not only do you need a good record but they must like you or have faith in you as well.
This is all just to start the course because then , of course, you have to pass it.
No training at CX...just checking. Over and over again until you get it right.