Pirate
I agree with some of your post but it does not protect the F/O.
Say, for example, Erates Airline is looking at a huge expansion over the next few years. The F/Os are rubbing their hands with glee, they have done their time. Then doom! Cspecific goes t*ts up. Oh-oh, all those highly experienced Cptains are now on the market, all type rated too!
Without a seniority system, and a no direct entry command rule those poor guys will sit on the right for years to come.