Things are unpredictable and always have been. Ponder this, though. There are about 2,200 pilots on the 777 (it is hard to be exact as the company no longer publishes a seniority list- you might want to ponder the reasons for that as well.) Officially attrition is 4 or 5%. There is no expansion on the Boeing for the foreseeable future, in fact there is contraction. With 1,100 first officers above you and attrition of 4% it will take you 25 years to get a command. Of course, that might change in either direction. Do you feel lucky?