How does "Normal" human achive high attribute score in universe?
Space Marines spend like 20h+ per day training and at age of 20 have like 15years of army experience and they start with 4 strength and 5 in the rest of their attributes.
So how does a mere mortal achive their species max attribute which is 8 across the board?
Decades of Training? Performance-Enhancing Drugs? Genetic modifications?
Like no natural talent beats geneseed+sm implants for gains by a longshot, But a mere mortal can have 8 strength or toughness while space marine starts with 4 and 5 in those?
So how?