I grew up with the notion that one needed a day dress/outfit (not a business suit), a cocktail/semi-formal dress/outfit, a real evening dress/outfit, something appropriate for a wedding (one of the above will normally do) and something appropriate for a funeral, plus business, casual and grubby/sports-specific clothes, quantities and styles as indicated by lifestyle and climate. This was called a "wardrobe" and it was built over time out of good quality clothes, to an actual plan, rather than through the mindless accumulation of random clothing items. Or so I learned.
I travel for work, and almost always wear trousers. I have two "all-purpose" black suits that can be dressed up to evening or down to business as needed. They are my go-to outfits for nearly everything, and certainly a funeral. My warderobe is based on black, because I can wear it, and it makes packing easier and one's clothing bills cheaper if everything is in one color family. If I based my wardrobe on brown, navy blue, or green, I would find those colors just fine for a funeral, provided the outfit appeared appropriate in style, and I wouldn't blink at a print dress or bright blouse as long as the outfit was a daytime style. I raised my children with this notion of things a basic wardrobe requires -- adjustments to dinner jackets and at least one dark suit for the boys, and, yes, they own them -- but nobody seems to do this any more. People have clothes, but not wardrobes selected to cover all the social bases one touches in daily life. I can see a younger person having nothing but a lot of very casual clothes for everyday wear and one very dressy cocktail/evening dress bought for a prom, because jeans and T-shirts are all most people ever wear anymore. I'd cut the kids a pass, but hope that somebody puts out a "How to Build a Great Wardrobe On A Budget" book for young people soon.