$300,000 is for n/b CA's. If they're young enough, which being 2000-3000 numbers less junior, and three years older, almost guarantees they won't be, they'd be w/b CA's and the additional years are worth more than $300,000.
And that doesn't count the in between years where'd he be making $15,000 to $60,000 more by being more senior. Or getting holidays off that much quicker, or summer vacations that much sooner. It goes on and on.
FO, who will retire as a 777 CA - "I'd kill for 2,000 numbers." Three thousand? Too depressing to talk about. A complete different life.