If the aircraft was attached to the ground the IAS increase/ decrease would last for as long as it was windy. In the air as the plane isn't tied down just the ground speed will decrease with IAS remaining the same as the wind speed increases and hence the IAS target is increased in the computer to maintain the groundspeed at a safe level in case the wind stops / changes direction. A party ballon isn't flying through the air it is flying with it; IAS zero, Groundspeed = Windspeed. Now if you are trying to go to a macro level become a scientist, buy a microscope and forget flying for a career.