Real achievement is. Neither you nor I will ever will the Nobel Prize in physics even if we spend the rest of our lives studying physics. That is a genetic limitation.
You'd be suprised at the cutoff vs. amount of work for several fields. Mozart was redicolusly talented in music, no doubt about it. At the same time, he'd recieved over 3500 hours of musical training from his father before turning 7, and he hit his high point after 15+ years of composing/training.
Bobby Fisher was a genius, yet it took him almost 10 years to get to the top, even though he played chess for 15+ hours/day many days.
There are really no to very few die-hard "naturals" out there (people who almost did no work and still became the absolute best). For people above the "threshold" rate in a given field, the amount of work = the biggest determining factor. Of course, the "cutoff" for some fields = stupifyingly high. The Mr.Olympia for example.