Anecdotal data, admittedly not perfectly analogous.
I got serious about playing the game of go relatively late in life for a go player--I was 23 years old at the time. In 2 years of hard study (1~2h/day, and a bit more on weekends) I rose from essentially a complete beginner to dan level play. Since then, life has pulled me away from playing go as actively, but the work I do at this point does let me maintain my level of play.
I think it's fair to say that you get MORE out of your effort at a younger age, but at the same time, I think that if you're serious about learning and honest about the way you learn, you can absolutely get a LOT out of those hours--and that ultimately, you can get the same utility as you would have, by tailoring your studies to the way you learn more effectively.
I got serious about playing the game of go relatively late in life for a go player--I was 23 years old at the time. In 2 years of hard study (1~2h/day, and a bit more on weekends) I rose from essentially a complete beginner to dan level play. Since then, life has pulled me away from playing go as actively, but the work I do at this point does let me maintain my level of play.
I think it's fair to say that you get MORE out of your effort at a younger age, but at the same time, I think that if you're serious about learning and honest about the way you learn, you can absolutely get a LOT out of those hours--and that ultimately, you can get the same utility as you would have, by tailoring your studies to the way you learn more effectively.