For SIA,
You will be told that it is about 8-10 years after checking out as a FO.
In reality, you seldom see anyone who is considered fit to attend a command selection "tea party" with less than 10 years experience as an FO. Let alone be selected for command training.
All in all (including training if selected) you are looking at 12 years.
As for cadet who is joining now, you have no hope in hell, as the bean-counters in Flight Ops regards that command training is more costly than a direct entry captain.