The most important feature of a launch site is having no populated areas downrange. Kilimanjaro would have Mombasa downrange.
I don't know of any launch sites significantly above sea-level, the marginal performance increase wouldn't be worth the logistical nightmare. It's easier to fly up a 747 than build a launch facility on top of a mountain.
The description of a space elevator falling is rendered in horrific detail in Kim Stanley Robinson’s Mars trilogy.
Twice.
Because the only known material strong enough at the time was diamond, and diamond doesn’t ablate much when falling through atmosphere.
One of the early space elevator research companies specifically designed a cable that was made by stacking successive layers of material both to slowly increase carrying capacity by building the tether in iterative layers, and hoping it would ablate or at least reach a quick terminal velocity in the case of catastrophic failure.
It is undoubtedly the case that the senior staff on that project were familiar with the Mars trilogy.
I've often wondered if we could decrease the difficulty of a space elevator by a good bit by integrating magnetic levitation.
The base would need to be enormous and I'm sure the power draw would be insane, but being able to break the elevator cable into smaller lines and take the weight off of any individual strand might make it a touch more plausible without currently non-existent technologies.
Mombasa is the shortest path to the ocean from the top of the mountain, that’s true. However that is not a good angle for an equatorial orbit.
What’s the downrange safety cone look like for space launch sites around the world? A little S curve in your insertion orbit would certainly waste a bit of delta V. But not all orbits are equatorial anyway.
I don't know of any launch sites significantly above sea-level, the marginal performance increase wouldn't be worth the logistical nightmare. It's easier to fly up a 747 than build a launch facility on top of a mountain.