Any tree near civilization that someone wants to pay to cut down is likely going to be at a distance from a structure, powerlines, or pipes in the ground (that's also the reason they want it removed) where felling it as it lies is not likely an option which is why you see them sectioned down or done with a crane or bucket truck. A lot of these trees done by tree care companies in residential or commercial areas are also sprawling hardwood trees like oaks that can't always be safely just dropped from the ground even if there's a clear area to drop it in. For logging or wildland firefighting, most of the trees being dropped are straight growing softwoods like pine or fir that are just dropped from the ground (or by machine).