“Seems to me that with the advent of multi/hperspectral technology “
Hyperspectral cameras are very expensive and touchy to environmental issues. At 200K and up, they are division level tools. Very few are small enough to put on a UAV.
We need squad and platoon level tools for this, and the price point for that will be 10K or less. Or a solution that will fit on an average UAV.
Trust me, there are people working on this and other aspects.
One trick the bad guys use is to bury a new bomb where EOD has just removed one, so the disturbed earth is overlooked (the assumption will be that the fresh dirt was caused by the EOD team).