Who promised you a left seat anyway?
It is interesting that many young stallions on this thread seem to feel they deserve command simply because they have chosen flying as a profession. They are the ones who want the more experienced guys to be dismissed so they can advance to the left seat. They feel they "deserve" it.
We started this profession to be a PILOT. If you are a pilot, congratulations. If you work hard, pay attention, show wisdom and maturity, then you might have an opportunity to fly in the left seat - not because someone more qualified and experienced than you has been forced to retire by an age limit.
By the way, I am 62 and flying left seat on a Jumbo. I am at top of my game in the airplane. I am having a blast, love doing it, and by God I earned it after more than 40 years of study, passing checks, and staying fit. You want me to retire after all that time and effort because you "deserve" to have my job? How long have YOU been paying your dues? Five or ten years?
Baloney!