I just looked up the cost of Oracle Kubernetes Engine on OCI (Oracle Cloud) and it's provided for free, you only pay for the compute resources you use.
On AWS you pay something like $0.10/hr/node.
Also, where do these machines run? What regions are available? What IAM controls and security policies are available? What is the disaster recovery story? For most real businesses, controlling and guaranteeing these aspects and risk factors quickly become critical. Far more important than saving a couple of hundred bucks or even a grand a month.
I understand.. it's sad to realize these things, because a better Heroku PaaS is highly appealing to the developer in me.
Perhaps there's a market segment I'm unfamiliar with which is craving this product layout. I wish you all the best.