>>57754261Some people are super touchy about canon lore so be warned the following is no longer canon and mostly attributed to poor translations, but gen 1+2 originally had some lines implying that pokemon were a new phenomenon in universe, hence the 'discovery' of steel types in gen 2. Jasmine 'found' them when her Onix evolved to Steelix, and Magnemite was recategorized. It's just old, forgotten, discarded lore that has no consequence.
Just honestly wondering where you entered the fanbase so I have an idea where people stopped learning the above, no genwars bs.
At this point the retcon can just be spun as Johto being so backwater rural that they simply hadn't had mass exposure to steel types yet.