There's an oversimplification going on here, I think (in the article I mean--the experiment is simplified for a good reason). The "one place" that all of these

There's an oversimplification going on here, I think (in the article I mean--the experiment is simplified for a good reason). The "one place" that all of these strains reach is that they are more fit for the environment than the starting point of each. This is not a new idea. This was the thesis of "On the Origin of Species". As for the level of fitness of each strain... after sufficient generations, basic statistics would tell tell us to expect this result. The combination of random mutations influenced by one constant factor (natural selection in a fixed environment) over a large number of generations implies this result. But the article appears to assert that this means that evolution's course is predictable. But what's not addressed is how each strain is succeeding. They know that the variations in the genes from strain to strain vary quite a bit. Yes, the result measured from one statistic (growth rate) is the same, but future evolution and other traits of the yeast will be influenced by the particular paths taken. Finally, once you put this mechanism in an environment filled with millions of other competing gene pools and a varying environment not bound by natural selection which means there's an actual threat of extinction, then that's where the true variability of the process emerges.