Compare to Deis, who built a Heroku analogue that you can run on your own compute resources. It was wildly popular for a little while, and then when it turned out there wasn't really a market for it, they simply had to leave it behind. (Today, that's known as Hephy Workflow, full disclosure I'm one of the maintainers of this FOSS project.)

Workflow and previous versions of Deis, as well as Dokku and friends also depend heavily on Open Source contributions of Heroku, so it's somewhat misguided to say that Heroku stays proprietary. They have been "leading the pack" when it comes to Open Source implementations of buildpacks, also Cloud Native form which you can find at buildpacks.io—and they set the original bar for a developer-friendly PaaS experience, which is still basically unrivaled even in the current era of Kubernetes product explosion.

We often ask about Workflow: "why isn't this particular technology several orders of magnitude more popular" and struggle to explain it, since it makes perfect sense to us and of course whenever people try it, they usually love it.

But Deis saw the writing on the wall, shifted gears to be some of the early Kubernetes experts when it started to become clear who was going to win; invented and open sourced "Helm" the K8s package manager utility, which is still very popular by comparison, one of the leading ways to package stuff for K8s. And then Microsoft scooped them up.

Agreed.

I think Heroku did a number of things almost better in terms of a deployment / dev story? But getting past the pricing was super hard.

The pricing is way worth it if you do the math on the number of engineers you won't need anymore

I don't disagree - but when you start your budget is so small that you worry overly much about price "if you get big".

Then when you have a budget you are used to other systems -> so it's a learning curve to get back and switching costs are higher.

or even better if you consider the Product value of what those engineers _could_ be producing instead.