A failed experiment is still a completed experiment.
Failure can be a note, a postmortem, a comparison, or the reason the second attempt worked. I do not want the site to only show the versions that shipped.
Show the middle when it exists: question, sketch, rough prototype, the implementation that did not work, the redesign, the decision. Any of those can be publishable. The first time a project appears online does not have to be the launch.