This kind of statement is akin to the many people that come up to me and want me to teach them "programming" because they see that I can do a lot of cool stuff and get paid well. They don't consider the years of no social life in high school and college and the many many many nights of no sleep while studying for exams or finishing up a computer project. Along with the years after college making a name for myself in my field.
10 years after getting my degree working and some punk kid comes up and says..."hey, can you teach me Java?"
I don't claim to know that much about the acting industry, but most of the big names have been in the business for years and who knows what they did before that to get to where they were. Tom Hanks didn't start out as Forest Gump, even though every snot nosed kid would say "I could do that...life is like a box of choc-o-lates".