there are only so many questions you can ask about e.g. how to write a CSS selector before all the others are duplicates Right, but there's a stagger

there are only so many questions you can ask about e.g. how to write a CSS selector before all the others are duplicates Right, but there's a staggering number of permutations of other factors. Think how many ways there have been to center a freaking HTML element over the years! There are, at a minimum, at least 10-20 "correct" answers to that question over the years. Even today, that answer varies a lot. What is your render target? A state of the art desktop browser with automatic updates turned on? Browser in some locked down corporate/government/military environment that is 5 or 10 or 20 years old? HTML embedded in email? Some combination of those? But Stack Overflow's design lacks that kind of specificity - there's no metadata associated with questions that would reliably specify the specific environment and software/library versions being targeted. And even when the person asking that question does give that information, the moderators don't have the time or the inclination to manually and laboriously parse out those specifics and compare them to the specifics of the other possible dupe candidates... a comparison space which grows by zillions of candidates per hour.