The problem with Wave wasn't that it missed its target as much as it was that the folks who "got" what Wave was about were largely the same folks who were already using Lotus Notes/Domino to its full advantage. I've worked in shops where people lived in Notes, and in shops where people lived in email in Notes, and there's a vast difference between using an integrated collaboration environment and messaging links and attachments back and forth.

It's funny, in a way, that people have a hard time putting the pieces together. They seem to "get" email, instant messaging, publicly editable documents, wikis, blogs, "related links" sidebars and so on...