When will people learn? A Service entails more than an oil and filter change
Not a lot else to be honest, at least that takes time.
A decent service:
Air filter - 5 minutes while the oil is draining
Plugs - 10 Minutes, again while the oil is draining.
Fuel Filter - 15 minutes...while the oil is draining.
I'm sure most places won't do a very good job in 30 mins, but it's not impossible.
Also plugs and fuel filter are every 30k~
The cars oil doesn't have to be piping hot, just warm i.e. like it would on the journey to the garage. Oil is the most important part of a service, most other things will either give you a warning/stop the car working properly or won't cost the earth to fix if it's a few k overdue.
IMO i would change the oil every 6k if i was doing lots of short journeys, and i know with older cars the damage may already have been done, but that why you buy one your confident in.