Trag Hi,
As everything in life the time frame to command will depend on supply and demand. If the airline has sufficient number of captains it will be a considerable time to command, if however the exodus continues and the turnover is high you could anticipate a command upgrade withing 3-4 years.
With all due respect I hear several of our F/O's complaining about when they'll get command but they don't focus on the real issue, preparing for the command. To be offered the chance to command is not the same as getting command, you will go through evaluation, interview, training and checking. A laborious task which is quite demanding and requires both good preparation and above all self discipline. I sincerely hope things go well for the airline and the command upgrade continues at the present tempo. But if I may offer some of my meager experience, my best advise to you would be don't worry about command, strive to increase your personal standards to the highest level possible and command will come.
Best regards and safe flying
A340Jock