I don't think any current locks prevent clearing the device for resale, which is the main thing needed by thieves. An iPhone, for example, you just hold down power and home and connect to iTunes in recovery mode.

Apple may in the future decide to do this, but I don't think any other OEMs could. They all have romance the carriers to get into stores and the carriers want good serviceability since the way you make money at places like AT&T is by cutting costs down to the bone. More unrepairable, unrefurbishable devices that need to be replaced with new units causes the opposite.