The bottom line
Most people have only slept on a few different beds for their entire lives. That leaves a lot of room for experimentation and potential sleep improvement.
The problem is that beds can get extremely expensive, so you can’t just buy a few and try them out, like you can with supplements. So it’s critical to understand if there’s any evidence or mechanisms for sleep improvement from different bed types, and it’s also critical to test out bed types (for example, by noting your sleep quality after laying on different beds at hotels or Airbnbs).