I completely agree with you. Yes Wave had issues (speed, invites, wrong marketing, etc) but the real reason it failed is because of all the morons who couldn't think outside of their limited mindset.
People are resistant change, it's widely known. Try to change people's crappy software for fun. Try to show your office coworkers how to use OpenOffice.org instead of Microsoft Office. They'll probably all hate it, but for the wrong reasons.
Wave solved a metric ton of problems, yet half the comments here and blog posts about Wave's failure mostly consists of "A solution looking for a problem."
Since october of last year, I have been using Wave extensively, every single day, with a group of people. Some are friends, some are colleagues. We have waves for casual chatting, where we just talk and share stuff together, and we have work waves were we discuss projects, and plan work, share files, have meetings, etc.
It's much more effective than threaded/replied/forwarded emails to get any kind of discussion going with a group of people. Emails get impossible to track really fast when several people are all replying to other people's messages. It gets messy. In wave, it's all neat, organized, threaded, and can be moderated. Delete a few messages that were not on the subject, move stuff around.
I can't wait for a stand alone server so I can host it for me, my friends and colleagues.