What are the most defensive types overall, and their histories?

Question

Like what are the most defensive types overall and how did they influence the game in each generation?

Comments

Why the downvotes? This is a decent question with tangible answers.

Answer 1

Rock was made to be the "defensive" type for first gen. But then, the psychics was too overpowered so in second gen, they introduced Steel and dark to counter psychics. Now steel is the more dominant defensive type.

Comments

And because of that, fightting, fire and ground type moves are so popular on competitive play

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yeah, because you can argue that they over-compensated when they made steel/dark and now you kinda need something to deal with those.