The OP is completely on track. Nothing saves an auto trans like regular maintenance/fluid change.
Yes, there are quite a few high mile auto trans that never get changed, but a MUCH smaller # than those that do get maint.
I beat on my 2002 Allison 1000 pretty good and with a Transynd change and regular filter changes it was running like the day it left the showroom at 150k when I sold it.
ALthough that's the beauty of a manual trans. At 120k my G56 has now gotten only 2 oil changes with good synthetic oil. Recent change was at 100k. Plan on changing it again in...........about 5 years!