While I'd say this is currently true, answers on SO tend to stick around for a long time, and the 'marked as duplicate'-heavy behavior means that even if the best practice to solving a given problem changes, the top SO google result won't. While this isn't a _huge_ problem right now, with the way the site is set up I only see it getting worse, to the point that some years down the line I imagine many SO answers will either cease to be relevant or push people down the wrong path when solving a problem.