Mostly, because we don't know where it is.

There was no EDL telemetry, so the failure sequence is unknown.

For example, if the parachute failed to deploy, or shredded instantly, the craft would have followed a ballistic track and ended up downrange (and with no intact chute to image). If the parachute worked reasonably well, but the airbags didn't, the location would be uprange and downwind.

That range of outcomes spans many tens of km across mars' surface, requiring many tens of detailed MOC images.

Remember the search for MPL? They ended up photographing an area 100 x 30 km and still didn't find it.

NASA can't afford the loss of time and science to clean up ESA's droppings. If they had done a proper job, with EDL telemetry, we would know better where to look, and the Beagle team would know what they did wrong.