Single Status Update
I kinda like to think that everything Eggman did in Sonic 1 - 3 was to build the Death Egg as a massive robot factory, and that he was only at the islands to pillage resources. That's why most of his machines and badniks don't look purely combat oriented or look like animals: They're actually construction equipment and the animal forms were a half-assed attempt to make them "blend in".
Eggman legitimately did not expect to fight Sonic so he and his robots pretty much had to improvise with whatever the hell they could find. Also the various powerups lying about like the Flame Shield, Electric Shield and so forth were actually supposed to be for his robots' usage in certain terrains, but Sonic was so much faster than the badniks that he usually ended up using them instead. It was only in later games when Eggman wised up that he started focusing on more combat oriented machines like his Egg Fighters and Egg Pawns (although the latter is more a middleman between his badniks and the Egg Fighters, since he still needed construction worker robots to build his stuff), and stopped dropping powerups as frequently as he did during the Classic Era.