It simply comes down to hard work and what you're born with. Talent goes nowhere without hard work.
Talented? Yuraslov Popovich. 3rd in the Giro at 23 yrs old. That's frickin' talent out the wazoo. What will see his greatness in 10 years? His mind, his focus and hard work.
Ulrich has talent. Once he gets off his fat ass, he's unstoppable. Not enough hard work.
Being a GC rider is genetics. Winning races is hard work and mental focus.