Yes, but top players will not need to have those habits fixed...
If you want to reach the top, the players definitely have to sacrifice themselves to train and definitely a 8hr/5hr course per week is not enough.
Is it a surprise that most world class players were raised from the slums and had football as their only friend ?
If your talking about structure and philosophy, 3 hrs probably differ a lot but if you have your heart set and have the talent, I dont' think 3 hrs is the soul reason the academies are not producing as much talent as probably Barca...
If you really know Barca, they heavily invest on youth, they track all the players in the South American regions and its really easy for them as they do not have any work permit issues etc...
The lenth of training isn't the soul reason imo.