Take for instance the songs the instructors have on this site. They are awesome and this is a site full of talented instructors. But, when you learn that lesson, you can hear a slight variation from the original simply because it is not the original artist. It's no less awesome though.
You are trying to emulate the time and feel of another person, that is very hard.
To the part of the conversation about 'talent'. Talent helps but I'd had a great friend and music mentor a great many moons ago point out that great players play constantly. Steve Vai can probably play anything by anyone, but he practiced an insane amount of time in his life.
This means that he has played different styles of timing, bends, vibrato and melodic patterns. He has that catalog to draw from. I'm guessing none of us here can claim that...so we draw from whatever amount of time we've invested.
That said, a natural feel (talent) for the instrument does help and makes the take off a little quicker. However, guitar rarely has any shortcuts. Talent only gets you so much before you have to do something to improve it.
