I literally think it's mentality only. I hate to be the one to make the argument that hours don't really mean much, because I'm someone who can put in the time anytime they want, but I think with some fair logic it's pretty easy to conclude the amount of time invested doesn't mean much either. It's literally what you do with the time. A player like me has over 10k+ hours in the game, and plenty of invite players and IM players could out DM me and they have a total of less hours than me. This is simply because the hours they actually invest to the game is towards contributing to their DM (where mine has mostly been somewhere else). I think hours is a grossly over rated concept and people use it as a demotivating factor, which leads more into mentality.
I've seen plenty of 'up and coming' players that I believe have the ability to be top level players. I heavily believed - and still do believe - talent exists in Invite that could topple froyotech. The problem is the determination and the optimism. I feel like optimism is so out of place in this scene. People are so used to accepting the fact that this game isn't going anywhere, the time is useless, and all that yadda yadda. Yet they still continue to play, and most of these people for the sole purpose of enjoyment of the time. Most players of this game have a good basis for optimism, which is enjoying themselves. However I've seen these same players constantly find excuses for why things aren't in their favor. Dying because the enemy team was dumb and not them, getting 'unlucky' with the game, they don't have 5 ping, etc. Every single player that has ever been at the top has almost guaranteed gone through same shit as these players, yet they reached the top while most don't. I heavily believe it's because they don't let these factors hold them back from wanting to improve. I think most up and coming players let their natural talents develop them, but when it comes to putting in any actual effort, they let these factors hold them back. I think that pretty much separates the top level to the bottom level.
If you want another example (that I love) you can look at our first match against Froyoblack in the most recent season. I dropped 6 times and we lost the match. Now I can go on that was literally the worse match I have ever played and how many things came into affect my mentality that day, but that's pretty irrelevant towards why mentality can make players good. It's pretty obvious we lost that match solely because I was having an extremely bad game. Do you know what Froyotech did compared to what any other team on the planet might've done? Instead of just writing off the loss on me having a bad day and going on with themselves, they looked for any other reason they could for why they loss. They analyzed the game and didn't include any mention of the drops I've had, they made it a nonfactor. A mentality like this is why some people are better than others in my eyes. Any other team in this game would've looked at my stats, and just wrote it off.
I do believe there is such a thing as natural talent. I also believe that anyone with the proper mindset can overcome someone who happens be more naturally talented than them yet have a poor mindset. One thing people should remember is to also remain optimistic. Being optimistic doesn't mean you have to be disappointed that you lost, it just always mean you have room for improvement. That's a good thing.