It might be possible Ferengi also have higher-than-human-average neuroplasticity and simply adapt easier - this might even aid in the on the job theory.
I think you're on to something.
Various Ferengi having a kind of genius foreign to Federation values is a recurring theme in DS9.
Nog, in particular, gets up to some antics that probably require some brilliance. I recall him hacking or circumventing things even early in the series.
The key lesson here is that anyone can find $25 / month to waste on WebVan stock.