Hard work is not always the end all to be all. Having a hard work ethic is always necessary, however, to achieve any success no matter what it is we do. Hard work advantages us, but it does not guarantee our success.
In every aspect of our success there are certain talents which we have that also play a role along with that hard work. It really does take both. You have to be good at what you do, and you have to have the passion and the commitment to do it—knowing that even with talent comes work.
You can go to medical school for 20 years and never become a great doctor. You can write 100 novels and never become a great writer. You can play a guitar for 10 years and never become good at it. All of the above require hard work, but do not necessarily equal success without having the talent to heal, or write, or play a musical instrument.
There is that old saying that you either have it, or you don't. It's the honest truth.