That's a serious tl;dr but I read the "In Conclusion..." part and I think I understand what it's trying to say.
I think that you don't need natural talent to be really good at it, but I think that some people that have a knack for a particular skill or art will pick it up and learn it much quicker and master it at a much higher rate of speed than someone who is inherently bad at it.
Like let's say you have very limber and strong fingers. You'd make a good guitarist. That doesn't mean that someone with terrible hand-eye coordination or some other disadvantage couldn't be a good guitarist, it just means that they would have to work at it harder and longer than the first person.
Also there's really a physical limit to how good you can become at something. I can practice every day of my life starting right now to become a figure skater, this includes weight lifting, running, training, skating practice etc., and I'll probably never be as good as someone who has done the same thing as I have but has other physical advantages.
You need to understand that we're not all equal physically and mentally. My friend and I could start practicing some skill that neither of us have ever done (let's say, wakeboarding) and at some point in our training, one of us will reach our physical or mental limit. At some point, someone just tops out on what they can accomplish. If my friend has a lower center of gravity or faster reaction times or whatever it takes to become a good wakeboarder physically or mentally, no amount of training will remedy that for me.