>>58179657
You don't understand, anon. They didn't think about that. The knowledge that GF employees extends to Pokemon balance is minimal and they rarely look back.
Grapploct is in the same field where it should be water fighting, but it's pure fighting. They made Tinkaton the Corviknight predator because of the move smack down, but gave it no good attacks against it.
Electric typing was also going to be super effective against steel types but that got shafted for some reason.
They probably saw that ground was a top tier type and bug was just a meme ass type and gave Flygon ground for STAB earthquakes.
Look at all the bug types in Gen 3. They had NO moves. In fact, a lot of the moves they did have were normal or ground. Flygon was probably ground type as a bug+ type.
The only two moves bugs had were Megahorn and Silverwind, Megahorn for Heracross, Silver wind for the butterflies. Everyone else, Flygon included, got fury cutter, and that was in Emerald. Some tester probably saw the moveset, sand tomb, dragon breath, Crunch and Rock tomb and gave a memo that Ground typing would be more formidable and fitting. Him and every other bug had bug move pools so shallow, that they had to give a fury cutter tutor in Emerald as the only bug move widely available. All the bugs had non bug type moves. Flygon being ground dragon at the time was probably their way of making him the apex bug pokemon. In fact, bugs resist ground moves, and Flygon is immune to them with levitate. Does it make sense now?