The assumption in benchmarks is of course that the results carry over to other use cases. Here, what is being tested is the overhead in recursion, nothing else. The fact that it happens to be Fibonacci-numbers that is being computed is irrelevant.
That shouldn't be possible. If you have a code example, I (and probably other people as well) will be happy to look at it.
Julia has a lot more potential for optimizations than python, but what python has going for it is the larger ecosystem. So if you want to write a one-off experiment that's similar to stuff that already exists in C bindings to python you should use that. If you plan to write a large application that you still want to optimize for current processors in 10 years then I'm not sure if python is a good choice.
The article would be much better if it ditched the comparison to Julia and instead showcased "Some ways to make Python code faster."
The benchmark investigated in the link answers the question "if I use recursion, and the function body is small, how much will I be penalized?". Changing the benchmark so that it no longer answers that question makes it pointless.