You gotta be kidding..............if that logic worked then there is no need to ever change oil in motor or transmission again.
Repair shops just love people that think like that. You do realize right that new fluid cannot help hopelessly worn out parts because someone can't think enough to figure out that old oil caused the wear.
If you change fluid and car quits shortly after, then it was not changing the fluid earlier that caused the damage, not the new fluid. One is either smart enough to figure that out, or he isn't. The trans shops are ready and waiting for people like that.