DuMmTmthought about that too after i found my first but it makes alot of sense to find more shinies in this, you can see shinies in the overworld and also see like 6 pokemon at all times, so even with the same odds as usual you are getting to roll the dice alot more/faster than in any previous game
in my case, the game just spawned a Luxray in my face during a rift, if it was say Emerald and i could avoid that encounter i would have and never seen that it was a shiny in the first place
This being said, I have seen data that basically says as the game progresses, the shiny rate is still 1/4096 per roll, but every pokemon that spawns gets more and more rolls to be shiny depending on what milestones you've hit, i believe maxing out at 32 rolls per pokemon, roughly 1 in 128 in an outbreak with perfect pokedex research and the shiny charm. So yeah, you see a LOT more pokemon in the overworld, but the chance of each one being a shiny is still higher than in base games by a large margin, hence why they're super common.