What possible reason could they have for not adapting?Okay, we didnt' see they couldn't adapt, we only say that they didn't adapt. For whatever reason they may have chosen not to adapt.
And you still have not proven that Drones can project KE fields. You're the one making the claim here: you are the one who must back it up. So far you've not done so. Provide evidence of Drones having KE shields or concede.
Wrong, they were all killed by the same thing: KE.And those later instances were all one off things with different weapons.