This is true on some level, but not true on another. The reality is that as web products change over time, they bring on new customer expectations. For instance

This is true on some level, but not true on another. The reality is that as web products change over time, they bring on new customer expectations. For instance, when searching for something with a finite set of possible results, the users' expectation is that they will see a dropdown with auto-complete suggestions. And on top of that, they expect to be able to navigate up and down the list with their up/down arrow keys. That, as well as a mountain of other examples, cannot be done with CSS.