The Gulf War jobbies were a lot less effective than advertised. Post war audit is what led to new weapons being developed.
MOP is only as interim, stopgap weapon, developed to cover the capability requirement against North Korea and Iran.
It is flawed in that it lacks a void sensor so can go clean through its target and keep going, exploding ineffectively some distance later.
Its replacement will have similar penetration capabilities but will weigh a lot less, it will use velocity in order to penetrate instead of just sheer mass.
Israel's lack of this weapon is one reason they haven't attacked Iran yet, they need USA involvement to do the primary bunker busting.
But the Iranians have developed a world lead in ultra high strength concretes. So even these MOPs might not do the job.
Interesting Economist article:
The economist: Iran makes some of the world’s toughest concrete | Pakistan Defence Forum