Every time this topic comes up you get the same group of people saying how hard work is key, muh 10000 hours, etc. etc. The point is that it's the COMBINATION of genetics and hard work. And guess what, they're intensely correlated because tasting some success at an activity is naturally going to reinforce the practice of that activity. I got hooked on running because I showed a modest amount of talent in it as a freshman in HS. So I started training in the off season and kept improving. If I had been struggling to break 20:00 that year I probably would've either quit or just kept participating as a fun diversion rather than a serious athletic pursuit.
Even a modest amount of talent reinforces the motivation to work hard. I respect the hell out of people who keep grinding even when they suck. But I'd be willing to bet most of the people on this board were like me and realized early on that running fast relative to their peers was satisfying, so they kept doing it.