My 2 cents.....
GA engines ( at least the great majority) run very dirty at full rich mixture and low power settings.
Inherent to the design, although they are supposedly air-cooled that is not entirely true.
The internal cooling is done by the oil and additional cilinder head cooling is provided by an (overly) rich mixture.
So ground running could do more harm than good concerning combustion by products contaminating the oil quicker.
In order for the moisture to burn of the oil temp needs to be at least 180F/100C and if you take a careful look at the oil temp on a cool day you will not reach that temp after the runup but quite a while later after take-off.
I guess I would change the oil after a winter of ground runs.