said by dynodb :

It's not "plain and simple" cost; you people sure have a way of beating a dead strawman.

RT's need to be accessed on a pretty regular basis- exactly how would you accomplish this with it buried underground? Keep in mind you'd need access all sides of the cabinet with room to work, while also keeping it protected from the elements and accessable even when there's a foot of snow on the ground, and providing for airflow for the fans in the Summer.

In order to do this, you'd need a very large hole... and then there'd be complaints about the 10 x 10 x 10 foot hole being dug in someone's yard.