Of course, one could go the other direction in terms of anachrotech.

Suppose that the principle behind contragrav, reactionless thruster
plates and inertial grav-comp *could* be discovered at any time after a
civilization learned to harness electricity (i.e., somewhere around TL-4
or TL-5).

What might a TL-6 balkanized world with indigenous TL-D maneuver drives
accomplish?