That is true, but in a persistent setting they likely also copy more data, and iterator invalidation might be a concern in some cases when moving values around within a B-tree node. The motivation was not really to come up with the best tree structure or to even consider memory hierarchy at all.

Instead, within just the scope of binary search trees specifically, what cool things might we uncover by taking a closer look? In a hypothetical future, our hardware might be so different and caches so large and advanced that the best practices of today might not apply all the same.

Binary search trees today are probably only viable for absolutely massive collections, and at that scale there is almost definitely a better, bespoke solution available. Exploring without necessarily thinking about the hardware, in the abstract, has been a fun sandbox to play in. The fact that we still teach them suggests that they provide value beyond practical application.

Thank you for your feedback, you are absolutely right. In most practical use-cases today, a B-tree would likely achieve better results.