Programming is very vast field and each kind has different requirements and challenges. In programming kernel, compiler or any complex software, the need of data structures is inevitable but in web development, you rarely need them and I can safely assume even frameworks build on high level language like Ruby or python, don't need them at all. Of course, there apps like Akinator which are an exception.

Some people believe that how web development is a cakewalk, in comparison. While it might be true to a certain extent since developers are cut off from challenges at lower level but there are difficulties that can take toll on you, trying to work with huge interactive JS application is no piece of cake, for instance.