Well the trans wasnt babied, but as a gm tech I know that there is a point where the trans is gone and you are begging on borrowed time but if the fluid is just wornout thats differant. You can flush for the first time after 50,000-100,000 miles if the trans was treated alright and the fluid is just changing colors due to age, by all means flush it. If you pull the stick and it smells bad dont flush it, your trans is screwed. Also transmission fluid has lubricating properties, I call it tranny oil for that fact.
the oil thing is how i explained it because, like I used to be, most know engines but transmissions are like brain surgery. I also agree that maintinace is worth every penny