Falcon 9 presently lands completely without any heat shield, because it just uses it's engines to reduce velocity until they are not needed. In principle, you can always replace heat shields with fuel like this.

Mars trips need to bleed velocity aerodynamically because the craft cannot bring enough fuel. Presumably a sub-orbital hop on Earth can save enough fuel to act as the brakes.

On earth you just need to survive, the speed is primarily reduced with the engines.

I suppose the reentry speed on mars is much higher, since it happens at the end of an interplanetary trip.