Whether or not it’s was a failure depends on what you expected from it. Reddit was not going to change its mind. The investors demand more money and will continue to squeeze Reddit for ever dime the can. It wasn’t going to die overnight either.
What did happen is a non-trivial amount of users left and found the Fediverse. Apps are currently being developed to make it more accessible to your average user. The Fediverse will no longer be some obscure thing for a niche group. I think it was a huge success and will have long term repercussions for Reddit.
Just like on Reddit, I don’t care. As long as it’s not tied to my ability to interact with the community then let them have their silly internet points.