With a large amount of experience, we as interviews, should be asking much more about past projects and issues people have run into. I find it much more valuable to understand what real world problems people have faced, and how they solved them. Sometimes you even get to a point where someone actually has a good story about using the wrong algorithm, and so you still get to talk about algorithms.
This tends to also tell you a lot about the candidate’s abilities to work in the environment you are thinking of placing them into. Algorithms questions should be a fallback only when you can’t discover this while running through questions about their experiences.