The only alternative is to have enough fuel in Mars orbit to do a retro-burn that virtually zeros the orbital velocity before you enter the atmosphere. And, by definition, that takes as much fuel as it does to launch from the surface into orbit.
No. There is no "definition" here, unless you ASSUME you are beginning from an orbit in the first place. But why should that be necessary?
Tricky, I admit, to do it differently, but that doesn't violate any laws of physics.
Plus all the infrastructure necessary to refuel and launch that vehicle.
You are fixated on Earth gravity. It is vasly easier from Mars, and again there is no law that requires "refueling". Lower gravity gives enormous advantages. Look at the size of the engine of the old lunar lander vs. the size of the Saturn V, for example.
Granted, doing it different ways might be harder, in some ways. But you seem to be locked in to one mindset, which isn't even necessarily valid to start with.