I have pondered this same question over the past few years since retire, and have concluded that several forms of “ black pants” are still essentials for me.
I think of 2 different directions-/ one is “ black bottoms” of more casual nature, such as joggers, to slightly more elevated Athleta Brooklyn. These are travel capsule essentials and, recently learned, “ staying overnight with hospitalized family member” essential. As well as, grab & go on errands.
Others are less everyday but still for more relaxed lifestyle- black linen trousers- I like the summer weight but more crease- hiding. Thd more polished styles whether wide or slim can also go to , alas, summer funerals, which occurred twice this year.
For dressy occasions, I am gravitating toward a capsule of midi skirts or classic black pants, such as tuxedo or slim. Black pants for a dressier evening are most likely to be something I can either keep for awhile or refresh more easily if my size/ shape changes. Similarly, black footwear ( or something that goes with black) is more readily available in styles my fussy feet could manage. Then dressy tops and/or jackets can be in more face- flattering colors, including tonal colors.
I’m still interested some types of ponte knits because they can combine comfortable fit with more polished look, and may be washable, which is also more practical these days. I have a couple of pairs in different styles still from “ career days” and would update if I saw something really good.
My days of collecting multiple types of dress wool pants are over, but bought some burgundy wool flannels last year for winter fun. But I would be on the lookout for a tropical wool or good flannel black ( or gray, charcoal) in a casual jogger style which I would wear enough in fall/ winter to justify the cost & upkeep.