Heroku has been around for ~17 years at this point. Why do you think it disappears in the next 10?
It's still there but feels like something different from what it once was.
Right now I’m in the progress of rolling out a new platform powered by Cloud Native Buildpacks that allow you to build an OCI image locally. Here’s some language specific getting started (local) tutorials https://github.com/heroku/buildpacks#heroku-cloud-native-bui...
Nice to hear about the buildpacks. I use Containerfiles but since switching to Podman and Fedora/RockyLinux I've seen stuff about OpenShift which supports buildpacks. https://github.com/sclorg/s2i-base-container/