I also myself from time to time think on that point; there could be something to such adjustments at least in theory.
However in practice, for example few pharmaceuticals are medically dosed according to weight or LBM of the individual: there’s simply a dose for human beings. It works. (There are some drugs which are, but most are not.)
Another example would be performance enhancing drugs such as anabolic steroids. In practice, dosing is not according to weight. It’s certainly according to gender and to past experience, but weight adjustment is rarely or ever done, and results are consistent across weight categories. It doesn’t seem important to dosing.
Why is this? Well, to some extent it may be from rates of metabolism and elimination of drugs or nutraceuticals not generally being a function of bodyweight. Another aspect is that even in cases where it’s shown that adjustment should be made for size, it’s not in direct proportion to weight, but instead generally in proportion to surface area of the organism, which is a smaller adjustment.
I’d expect that adjustment could well be applied to extreme differences: for example a 90 lb woman really is considerably smaller than what we have extensive experience base for, and some reduction (not proportional though!) in dose could make sense.
But range such as male lifters in general, there does not seem any need for bodyweight adjustment, or at least not upwards. There has not been any need for dosing in excess of 6 capsules, and this has included some very large individuals.