I no longer work in academia but what I observed when spending time in top-tier research groups is that it's at least as important where you work as how smart you are. You can be the most gifted researcher but if you work in a backwater university in a third-world country your chances of being noticed or doing well-recognized work are very dim. On the other hand, if you're a smart person working in a top-tier environment your chance of doing noteworthy work are much higher.
Now of course smart people will usually find ways to get into better environments, but from my experience there's still a lot of elitism involved. For example, where I did my PhD in France almost all fellow PhD students in my group had parents that were high-ranking scientists, some of them leading research institutes. I always thought that it would be extremely unlikely to observe such a concentration if the selection process was really unbiased. Not saying my colleagues weren't gifted, but of course they had a lot of advantages as compared to gifted students from poor families as their parents knew exactly what to do to get them into the elite programs (in France you have to prepare for this for many years, starting with picking the right school for your children). So being in the right place and having the right pedigree is still a huge factor for getting a good shot at being really successful.
[1]: http://hacol13.physik.uni-freiburg.de/fp/Versuche/FP1/FP1-11...