I mean, not a great example considering he used steroids (not as much as today's standards, but he still did). You also coooooould get there, but the amount of work, effort, and drive required would be insanely high, especially given that you don't give in to steroids.
OT: I'd argue yes and no. Some of your skill can be given to you through genetics while most of it is through practice. You can also get more through a mix of effort and drive. If you really, truly, want to do something, you can probably get there with enough experience+effort+drive, but the amount could be extraordinarily huge depending on the type of person you are.
Due to their drive, some people will simply never get better. Using WoW as the example, since you have, OP, a lot of people are totally fine with LFR and not giving a shit. These people won't ever get better until they put in the effort to get better; the drive to want to get better. When I was a teen and WoW had just come out, I just wanted to faff around and explore the world. I wanted to raid when BC came out, and by Lich King, I at least wanted to do 10H/25N. With Cataclysm/MoP, I wanted to push as far as I can go, but from what I've seen, I'm actually held back by the rest of my raid not having the same goal. WoD I pushed back to just Heroics, and Legion I had the same mentality, but since I joined a new guild, it's at least "a few mythics".
I know I could do better and probably even get Cutting Edge, but at the same time, I don't care enough to throw way too much time at the World First race and I'm comfortable where I am. Sure a handful of our raiders that have NO place in Mythics, I'd love to see replaced, but I just don't care enough to do so. I'm happy being 4/9M right now and usually being in the top 3 every fight, the guy to handle mechanics, teach people who don't, even going as far as making a 5m video on a single, simple, mechanic (I actually did that yesterday for Mythic Sisters because half the raid didn't understand Astral Purge).
TL;DR: Kind of. If you have the drive, you can do just about anything, but it will take a lot, and I mean a LOT of time, effort, and drive.
This is the true problem of any game that relies on the rest of your group. My guild is 4/9M (just got our 4th last night) not because of me, but because of what 25-50% of the guild is fucking up on and holding the rest of us back.