well y'see that box is meant to be protected by god himself, so if you destroy it you would have successfully proved god either isn't real or doesn't give a **** about us anymore thus rendering religion pointless.
I'm muslim but don't quote me on this as other muslims may be more knowledgable on this subject
But there's not been any proof, very convincing theories yes, but no concrete proof. I'm not gonna get into this debate on FJ because this is literally the worst place to discuss religion but I'm telling you man, destroying the ka'bah would pretty much end islam
if natural causes IE earthquake storm or some **** , probably they would try to rebuild it
if a group or country did it, probably every extremist muslim would declare jihad on said group/country. it'd equal to bombing lincolns grave or killing a moose in canada