Well, by setting all the variables to their mean values, you are stipulating specific values of all the predictors, and therefore also stipulating a specific expected value for Profits itself, and then repeat that with an increment of 1 in X. The difference between those is interpretable as the expected change in profits associated with a unit change in X conditional on all variables being at their mean values, but it is not applicable to any other combination of values of the variables. So it is a number of very limited usefulness since, in most situations, there are few or no entities that are actually at mean values on all relevant attributes. Code for this, doing it in one step, would look something like this:
Code:
margins, dydx(X) expression(exp(predict())) atmeans
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