Aerodynamically it wants to be aligned along the vertical axis. Similar thing for thrust forces. So at a minimum you want to decelerate all the way down from te

Aerodynamically it wants to be aligned along the vertical axis. Similar thing for thrust forces. So at a minimum you want to decelerate all the way down from terminal velocity with the vertical direction aligned to the direction of travel. And that only leaves a narrow window of time after which you could bother concerning yourself with reorienting. And, of course, reusing the main engines saves on complexity a great deal.