I've seen well-seasoned cast iron that was nonstick if you treat it the same way as stainless: get it hot before adding anything, and put quite a bit of fat (oil, butter, grease, whatever) in first.

I've not seen any that were nonstick at low temp and with no fat in it, as teflon pans are. I can cold-start eggs in a bare teflon pan with no butter or bacon fat whatsoever, and make totally fine scrambled eggs while keeping the temp very low the entire time. I've seen some extremely well-seasoned cast iron pans (and they are damn nice, and quite nonstick, compared to steel or new cast iron) but they couldn't do that. Not without leaving a mess to clean up after and losing half your eggs to sticking. You could cook eggs in them and nothing would stick, but you had to start fairly hot and add a layer of fat first.

They also leach flavors into everything, which really comes through if you cook anything delicately-flavored in them, and even well-seasoned ones are vulnerable to anything acidic and will leach a ton of unwanted flavors if you cook with e.g. tomato sauce.

I still like them for lots of things, but they're not magic. Teflon... kinda is magic.

Cast iron pans are great but no matter the level of seasoning it will it never be as good as a new nonstick.

unhygienic cast iron isn't necessary, stainless steel and heat control and steel wool are enough

Cast iron pans are no less hygienic than other pans.

Indeed this is a persistent myth. [1]

[1] https://campfiresandcastiron.com/are-cast-iron-pans-sanitary...

lol i'd like to see these germs that can survive at 400F pan temperatures lol

Cast iron is perfectly hygienic