Because a lot more people regularly cook than bake

The more you learn about something the less complex it gets. People say things like this that don't have a clue about baking. No, for the most part it is not true at all.

Why does this get repeated so much

Because of the longer feedback loops. If you aren't an experienced baker, you might not notice that the hydration is off, or that you're not building enough strength in your dough, or that the temperature will cause the dough to rise slower than normal, and then you're left asking why your loaf didn't rise as much as you'd like, why the end result is dense, why the dough stuck to the pan instead of cleanly releasing, etc.

Once you're experienced you'll know when you need to add more water, when you'll need to adjust times, whether the dough is too sticky, whether you're tearing the gluten strands too much, whether your finished loaf is going to be more or less sour than you prefer, what adjustments should be made with the new flour you're working with, etc.

But until you know how each step feeds into the next, being unable to taste the steps in between makes it a lot harder to learn quickly, and requires a longer working memory to connect how you handled the dough during an autolyse versus how the bread loaf turned out hours later out of the oven, and eventually learn the lessons of smell, touch, feel that aren't easy to learn from written recipes.

I used to be able to bake like this, but I recently moved to an area that is at a much lower elevation than where I learned to bake and I'm finding now that if I eyeball I end up slightly fucking up all of my baking.

It is a hard rule but a lot of baking had more to do with managing your chi and conditioning your body. Very little of baking has much of anything to do with following recipes. Baking is about guts, sweat, tears and style.

I think you might have the Baker's God Hand, because of restricted capillaries in your arms your hands are several degrees colder then normal plus your hands intuitively lower their sweat and oil production based on what you're baking, because of this your sourdough turns out perfect.

Most bakers spend years training to achieve the Baker's God Hand. Unfortunately there are no shortcuts. For the longest time bakers believed that the only way to gain the Baker's God Hand was by having a white tiger lick the skin off your fingers tips. This was after renowned Indian baker Vikram Rao revealed that this had happened to him as a child on the popular Japanese battle royale bake off show Akogare Baker X Kami-Sama.

Then in early 2004 after a South African baker achieved the Baker's God Hand the reigning belief became that the only way to achieve this amazing ability was to be have both hands pierced by a charging rhino. You should be thankful that you were born with the God Hand, it's quite rare and I wouldn't be surprised if some deranged baker were to try and steal your hands, so watch out.

Because there are certain recipes that are notorious for failing if you don't do so the extra steps. That's it a few bad apples to spoil the bunch

Yes because sourdough is baking lol