Pretty sure the only Gen I DIDN'T find a wild shiny in was Gen 4. Found a wild shiny Sandshrew in Union cave in Gold, found a Machop and either a Zubat or Golbat in FireRed (lost 'em as the cart was bootlegged and wiped the file when I tried to connect to Gen 4) and then found picrel in Gen 5. I did try and runaway hunt Shaymin in Platinum but ultimately didn't have the required 'tism level to fully send it and find it.
But that was in part the point of reducing the odds, increase the chance casuals will happen across one or two during their playtime instead of needing to invest serious time and autistic focus to produce one. Sadly autistic faggots think being abnormal is supposed to be the default, hence why they're still crying about the drop in odds.