OP has a good point about deployment. DevOps tools have made huge strides in the last few years and it's feasible to build something that approaches the conveni

OP has a good point about deployment. DevOps tools have made huge strides in the last few years and it's feasible to build something that approaches the convenience of Heroku's fully-managed deployment pipeline, but that's not the only value that a PaaS provides. You really shouldn't underestimate the amount of work that it takes just to keep a product running. For example, dealing with hardware & network failures, maintaining data backups, keeping up with OS-level security, & scaling up. That's a huge part of the value that Heroku provides for us.