The Salesforce acquisition closed in 2010, when Heroku was barely three years old.
A whole lot of Heroku's best features shipped after they were acquired. They had a pretty good run under Salesforce for the first few years.
It would be interesting to hear a full oral history of when and where things went wrong after that. I expect the original founders leaving was a major factor.
I think a lot of people are under the misconception that the Salesforce acquisition happened a lot later than it really did. In particular, I think people often implicitly date it to the late-2010s-ish period when Heroku's product emphasis got more visibly enterprisey, and in particular when it started putting integrations with Salesforce's other products front and center.
A whole lot of Heroku's best features shipped after they were acquired. They had a pretty good run under Salesforce for the first few years.
It would be interesting to hear a full oral history of when and where things went wrong after that. I expect the original founders leaving was a major factor.