>>49795018It doesn't matter what their BST is if they're still a shitmon. BST isn't the be-all end-all of viability, as low BST Pokemon like Smeargle, Diglett, Dugtrio, and etc show. Early game Bug-types being shitmons doesn't mean that early gens were cruel to Bug-types as a whole, nor does Unova adding a bunch of good Bug-types mean it was good for them. In fact, you could argue that Unovan Bug-types muscled out a lot of weaker and struggling Pokemon that filled similar niches in lower tiers. What truly helps Bug-type Pokemon is the addition of new moves and abilities that give a helping hand to the older Pokemon of the type, and Gen 4 is obviously the best Gen in this regard.
>Not to mention the most damning thing about Gen IV is that it added Stealth Rock, which would haunt Bug type until boots became a thing.Stealth Rock didn't haunt Bugs as much as it necessitated the use of Rapid Spin on teams, which it did. Bug-types still saw solid usage in all tiers of play in Gens 4 - 7, and it also punished Fire and Flying types, the only types that both resisted and are super effective against Bug-types, giving them an easier time punishing and removing persistent threats to the type. It was a double edged sword that more or less left Bug just as viable as before due to putting offensive pressure on the types that preyed on Bug.
