I think the real mistake there is that they waited until that high bar was hit before reaching out - if they'd started the conversation earlier they might have

I think the real mistake there is that they waited until that high bar was hit before reaching out - if they'd started the conversation earlier they might have figured out what discounts they'd have to offer to keep the business, got them on a long term contract etc. We used Heroku for years and were spending around $2k per month (having increased from $1K a few months before) when we migrated the last stuff to GKE and our spending dropped to nothing instantly. I was pretty surprised to have nobody at all reach out to us to see why our spending had changed... Now we spend 7 figures on GCP instead. Heroku solved a lot of problems incredibly well but they seemed to lose any ambition to be more than a salesforce deployment platform a few years after the acquisition and as k8s and other solutions have gotten better they just don't have a super compelling proposition now. I still use them to spin up side projects though as they still provide the best completely out-of-the-box experience.