No, this isn’t a cast iron thing. Using stainless pans, you can get nonstick effects that, in my experience, far outperform Teflon anyway. The process is called “spot seasoning.” I have cooked crispy, cheesy rice noodles with eggs with zero sticking.
I love my cast iron pans, but stainless is my daily go-to. Added bonus: use 100% copper wool to clean your stainless pan. The copper-coated wool at most grocery stores is problematic; you might get a few uses out of the coated garbage and then it starts shedding metal bits.
Been using the same set of pans for about 30 years. Just cold oil and a hot pan, get my food in immediately and same thing. I can slap pork chops in there no problem. I just have a feeling if I tried this instead of your method on a new pan, I’d be screwed.
I’m pretty sure the pan is just seasoned after that amount of time and they definitely get used daily, if not multiple times a day.
A stainless or carbon steel pan will take to the cold oil method first time. Cast iron will depend on the quality; some come preseasoned, but the quality of that varies a lot too.
I got my first nice CI skillet about five years ago and daily driving it. I talk a good game about steel pans but I just don’t enjoy them as much. You build their seasoning, it works perfectly once, then it’s gone. There’s no relationship, no satisfaction in getting a fried egg to slide freely about the pan.