Assorted thoughts:<p>- My wife's aunt was buried in a gravesite where multiple coffins were stacked (at least three deep, maybe four). That allows for more efficient use of space than does this screw-in design.<p>- Historically in Europe, you would only be buried long enough for the flesh to decompose and then bones would be removed to an ossuary. There are assorted "bone chapels" that show the artistic uses the bones were put to.<p>- Culturally, at least in the west, there is a desire to make it look like the dead person is asleep (although things always end up looking a bit off because, well, they're dead. At the last funeral I attended, for a high school friend, his skin had a distinct greenish tint to it).<p>For these reasons and countless others that I'm not going to come up with, I would expect sales of the screw-in coffin to total in the middle two digits. Maybe fewer.