It's not a static situation. The questions have changed, to the point where solving them in interview conditions is a separate skill. When I interviewed people at Google, I asked interesting but quite simple questions and they gave me all the information I needed. As a candidate doing interviews elsewhere I have often been asked questions that are way too complicated to actually solve in the time.

How we got to this point : as average candidates train more in interview-coding, the interviewers pick harder and harder questions. It's got to the point where the only way to reliably pass is to have pre-canned memorized solutions to hundreds of existing questions. It's an arms race divorced from the reality of the job, which is done with real world tasks, privacy, little time pressure, and access to reference materials.