Fair.Pilot
If you were to start as a cadet with a major flag carrier then you could reasonably expect thirteen to eighteen years to Command of a wide-body aircraft from the date they issue you with a number. An exception is SIA when local cadets can expect command after about ten years but this is unusual.
For a command on a wide body jet, from date of first qualifying to line in a multi crew environment, not likely to be less than ten years but nearer thirteen to fifteen would not be unreasonable.
In rapidly expanding airlines these numbers can be drastically reduced from time to time, but, rest assured, when it is your turn there will be an ample supply of suitably qualified chaps!