Oil change is maintenance not service. But ok, let’s include that. It’s done at the same time as rotating tires, so it only adds few extra bucks of revenue for dealers (yes, you can rotate yourself/at other places, same as you can do oil change).

Transmission fluid for modern cars lasts about 100k miles. So you’ll do it maybe once, unlikely at your dealer as you won’t pay dealer tax for an old beater.

Exactly the same for timing belt and spark plugs.

Drive trains aren’t money makers for dealers for a long time.