I've been using cast iron daily for about 15 years and prefer either a glass or stainless lid on my skillets for most situations (at least for normal cooking indoors).

since the lid isn't actually a cooking surface it doesn't benefit from seasoning, and often lids are getting exposed to a lot of steam. my cast iron lids often get rusty for this reason.

are you referring to stainless steel, carbon steel, or something else?

I bought an enamel Wolfgang Puck dutch oven probably around 12 years ago - mine didn't fare as well as yours, though. I used it a lot, took pretty good care of it, but the enamel started chipping. I got it new, but at a discount store, so who knows why it ended up there (no clear damage or defects when new).

I've had similar issues with some other enameled pots I bought used, but then have others that have patina but no chips at all.

I think the quality of the coating is what really varies from brand to brand.