What Causes Actors To Be Underrated Actors Like Leonardo DiCaprio?

Like if i do become a actor one day i hope i don't fall into that List because right now im 21 & i still havent taking any cles because right now im Readin the Ivana Chubbuck The Power of the Actor because for some reason i want to take cles in New York & Los Angel as...i dont want to take cles here in Michigan but yea is it the way they pick there Roles what?