It's frail because Gamefreak wanted to make it a mixed attacker so it could reliably run both Fire and Ground type attacks before the Phys./Spec. split, and all those points that could have gone into its HP/Defenses went into its Attack instead.
If it was made with the split in mind, you could see it with something like:
HP: 70 -> 90 (+20)
Att: 100 -> 75 (-25)
Def: 70 -> 75 (+5)
SpA: 105
SpD: 75
Spe: 40
BST: 460
