I have been cubing for about 4 years now. I have taken a couple of extended breaks during that time however. After four years, I have just finally learned 3LLL. My typical average is around 40 seconds, and I do have a couple pb singles of slightly under 25 seconds, although nothing even remotely close to that in competition.
When I first began "speedcubing," I had never met a speedcuber in person. All I knew was from the few online videos of the time. There were very very few truly informative sites for beginners. For those intermediate cubers, there were some sites to follow along with, but for the rest of us, we were pretty much on our own. My two best resources at the time were the yahoo group and Bob Burton's website. I recall many people on the yahoo group attempting to explain how intuitive f2l worked to me, and with a quick search, you can still see many of those conversations archived. At the time though, I had no one to explain it in person, and there simply were no tutorial videos.
"New cubers" are very fortunate these days. Between THIS amazing site, the vast amount of youtube tutorials (especially badmephisto's) and the general willingness of the general cubing community to share resources and tips with all those interested... there is never a lack of information to be had. There simply is no more guess work.
Every person is born differently. As has been stated, some people are geared more to coordination, some to strength, some to intelligence... etc, etc, etc. We are not simply "tied down" to these simple predisposed abilities however. We can still feed our abilities through our life experiences and develop new skills, although you will frequently find that some skills are much more difficult to develop for some than for others.
I believe that one day I will be a sub 20 second cuber, and perhaps with enough work I will make it to the sub 15 realm. Will it come easy, certainly not. Could I have already reached that goal if I had worked both smarter and harder? Most likely so, but I'm not sure that I would still be as interested in cubing if I were to have taken things "that" seriously.
^^Just some of my random thoughts.