Ok. Tell me who out in the world can bring down a B-1.
Damned near anybody. It is not a magical aircraft for goodness sakes! The militaries of a good many nations can take them down, Russia, China, most of Europe, Taiwan, England, France, Germany, Israel, even Japan could easily take one out.
This is why we try to only use them away from enemy forces that are a threat, or once air defenses have been taken out (they were not used in Iraq until Iraq's surface to air and air to air assets had largely been destroyed).
You seem to be seriously underestimating the capabilities of other nations around the world.
Hell, have you forgotten that Serbian forces shot down an F-117 with what is essentially a 40 year old missile system in 1999?
Nothing in our current military inventory is safe from harm. The closest I can think of out of all of our hardware in the last 25 years that was largely impossible to destroy were our Battleships. And the last of those was retired over 20 years ago.