I wouldn't say it failed yet, but the writing is on the wall. GitHub Sync has been down for over a month and they think all API keys leaked and... it seems nobody cares. Communication is at a minimum, the UI is broken, we have no clue if our API keys were leaked, etc.

It's clear nobody at Heroku cares anymore.

(For the record, I loved Heroku and still do. This makes me so sad. I'd love to see Salesforce spin it off somehow, rather than slowly letting it suffocate.)