Yeah, that's definitely true.
I think 23-24 year olds are the most expensive players on the market. A player might improve after 24, but only a little, so if he's world class he should be at an age where he can lead the team. You'd get at least 8 more years out of him, with a bit of luck Pogba might play another 12. I would value him higher at 23 than at 28, even if he's the better player at 28.