First, I'll say that yes, practice does matter, and then I'll tell you a theory that I hold very precious, and so does Mew2king:
The most important skill is the ability to learn. But just like anything else, we believe this ability can be improved. People that are "naturally talented" started with a high base ability to learn, but you can actually "improve" your "talent" and not only refine your "skill".
Talent is "your natural ability to perform". Skill is "your actual ability to perform". Skill must be developed and refined. However, I believe that talent can also be developed and refined. However, the method is different.
You have to practice your mentality, to develop your talent. Often times, you will hear a pro player say "You have to understand why you got hit or what lead to you landing a hit". But despite this seemingly obvious advice, many people don't pick up on it. Why? Because they do not have the right mentality for honing their talent, when this type of basic advice is actually targeting that. This advice is not telling you what to do to be better. It's telling you HOW TO THINK, so you can learn to be better.
I'm not going to teach you all the thought processes necessary to become like that, but I am confident that those of you who truly have the will to evolve into a top player, or to be successful at ANY aspect of life, will seek this out for themselves, learn it, and master it. The more you develop your ability to think and learn, the greater you will be at any endeavor you undertake, and the more "talented" of a person you will become.
Now, that deals with the natural talent part. As for practice? I cannot think of a top player who did not practice. Mew2king, dominant player, practiced for HOURS UPON DAYS UPON WEEKS TO PERFECT AND REFINE HIS SKILL. ADHD in his prime CONSISTENTLY PRACTICED. Nairo practiced in a similar fashion to Mew2king. Ally practiced. Vinnie practiced.
The reason you might be led to believe that practice doesn't matter is because practice without understanding is futile. This is why I never grew to be a top player, but I was always a contender. I learned how to be good, and I practiced at the same time, but when I truly attained the understanding necessary to be a top player, I was no longer practicing. I was getting outclassed by players who practiced more than me. And I asked myself "do I still have the ambition to be the best, as I once did?" And I answered myself honestly, "No." And shortly after, I quit Smash.
When I played 3rd at Brainshock Beta (my last major tournament), I think I played like **** to be honest, but you better believe that I practiced a lot. You might hear top players say, "I won and I didn't even practice" but what they really mean is, "I didn't prepare for this event specifically." Do not be deceived, all of the pros have put in hundreds to thousands of hours into the game, honing their craft, and take it quite seriously.