wantsmore, I noticed that I short-changed you on your 1st question (it’s late here).
If you consider an elastic band or a cable that is “stretched to the breaking point,” that could roughly illustrate the point I’m making about elasticity. You seem to be asking about the specific “mechanism” behind this. Obviously, when talking about cables, this would deal with physics/chemistry. When talking about the penis, you’d be dealing with biology.
I don’t know the exact medical explanation behind this, but I would imagine it relates to a question once posed here: “Is an 8-inch PE’d Penis Different from an 8-inch Natural Penis?”
I believe the answer is “Yes.” In other words, within the complicated biology of plastic deformation of penile tissues, I would bet there are specific “changes,” at the cellular level, with these tissues. Whether you’ve gained 1, 2 or 3”, these gains begin at the cellular level. I imagine there to be a deformation, at the microscopic level, which over time will diminish the tissue’s ability to continue deforming. This might involve some exhange of proteins or elastin, or whatever (that’s not my forte).
Realistically, for us to have any effective pharmacology/dietary approach to this, medical science would have to get involved in this field. And that doesn’t look likely in the near future.