Most of the places you cited are public (Ford's Theater, Mount Vernon, Pearl Harbor, etc.), not a private resident's tree studded yard. Nor would you want a bunch of people assembling in the street in front of your house to gaze at some monument.

Pointing out the woods on a bus tour of Nashville from I-65 is one thing; having people trample through the woods on this private man's property is another. Plus it is just morbid.

I don't think ANY celebrity would want to be immortalized at their death scene.