Alchemists are trained in how matter behaves and how to manipulate it... turns out they're not any more competent at it than anyone else. It seems obvious that a student of philosophy who has been trained in logic and critical thinking will be better at it than others, but obviousness is not in itself evidence. Lots of things sound obvious but later turn out not to be true.

The other thing is that you've made a dichotomy out of a quantitative problem: how much better are philosophers at it than anyone else? A little? A lot? Is it a skill that persists after graduation? Better at certain types of problems, maybe worse at others?

In any other context, on any other topic, a philosopher would never dare to make hand-wavey statements about how obvious and straightforward it is that X leads to Y. Only when it comes to their own field of study and its value do philosophers become sloppy and claim the value of their field is self-evident and frankly beyond discussion, or they try to turn it into an irrelevant meta-discussion about the nature of evidence. That's the irony I was pointing out. If you boast about being rigorous, be rigorous even when it doesn't suit your purposes.