The 4-year upgrade probably applies to one or two bases. If someone posted the most junior captain for each base, it would provide more perspective. I'd guess most bases still have 7+ year upgrades with 9-10+ years to hold a line. Also, if there is 2000 pilots on a list. Number 1000 would likely not be the most junior captain. The most junior captain would probably be closer in 1200-1300 range. The number of pilots on a list is also misleading because a percentage doesn't fly the line and when a company is hiring a lot, a percentage of the bottom is not qualified. Upgrade times are too fluid to calculate, too many constantly changing variables.