Kinetic orbital bombardment is utterly worthless from a military perspective.

People tend to have a completely inaccurate view on this because of bad popsci, out-of-context feasibility studies from the 1950s and fiction that just leans toward the "fantasy" on that.

The reasons for this is are very simple:

1) There is no "high ground". Being in orbit does not enable you to throw things "down" for free, thats simply not how orbital dynamics work. All the impact energy you have to pay for up front, and delta-v on some orbital object is almost inevitably more expensive than the equivalent amount of explosives on the ground.

2) Anything launched from beyond earth orbit would be unusably delayed. And telegraphed.

3) The concept does not have a single selling point from a military perspective; not really faster than an ICBM, penetration is limited by newtonian physics regardless of speed and more expensive than just delivering the equivalent amount of explosives (or nuclear payload) via missile.

edit: Yes an interplanetary transport system could be weaponized. But so could the explosives currently used in mining (~tens of millions of tons per year), no one cares.

If it gets separated at the asteroid the mass brought back is small. Total world production of Te is about 1000 tons/year.

I imagine a time long long ago, early humans debating the proliferation of fire.