I always figured that they just couldn't wrap their heads around a good way to monetize it.
It was painfully slow on netbooks, but it did work, and we used to use it to live-comment on LOST episodes with two other couples that we're friends with (but live in different cities, so we couldn't just have a watch party every week).
I mentioned this somewhere else in my comment history, but I once used Wave with a group of creatives to develop a theatre piece, and everyone immediately "got" how to use it. (We'll not get into the debacle of the next project where we'd collectively run out of invite tokens, and... Ah, Google sure self-sabotaged that, didn't they?) Totally non-techy crowd, but took to Wave with appreciation and joy.
A decade-plus later, in my present (grown-up / sellout) job, I evangelized Dropbox Paper - which was sorta Wave-like, if you squinted a bit - and it Did. Not. Stick. No one else could stand it, and everything reverted back to interminable document-attached email chains and more-interminable Teams calls everyone's invited to "just in case".
I can't tell you whether that's because artistic people are more able to think non-linearly than business people, or because Paper didn't get some special something exactly right. I wish I could run the experiment.
It was painfully slow on netbooks, but it did work, and we used to use it to live-comment on LOST episodes with two other couples that we're friends with (but live in different cities, so we couldn't just have a watch party every week).