[Louis Foxwell]

Or is it a case of solve the problems you can now, and hope the solutions for the ones you can't will come along later?

Well, DUH!
How is it possible to solve problems that are unforeseen or do not yet exist?

[Fatuncle]

This problem is foreseen, and exists now - the shuttle has come home more than once with a hole or ding from orbiting debris. And most of that is accumulated from stuff moving in more or less the same orbit, at much the same speeds.

The elevator "cable" would be stationary, and anything hitting it would be at orbital velocities or greater.