I don't know about the baking thing, but a lot of Pro Dommes I know are very artistic and are incredibly creative as people... Many of them do use food/cooking as one of the mediums to express this.

I am sure diet does play into it in some cases, but I actually think you missed the caretaking aspect of cooking for others in your analysis of why there seems to be a preponderance of Dommes with great culinary skills.

So, as ususl, my long-ass answer to your simple question is "no... I don't think you are off-base on this"
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Asp