This is a great blog and have so many insights for an SRE or devops person. But this goes to show you how difficult it is self host stuff at scale.
I used to work for a company that built deployment platforms for law firms. All our deployments where on prem and we had the same complexity with kubernetes. We had similar setup with vault and stolon for HA PG. More moving parts you have in infra, more permutations and combinations of failure modes you have.
What these guys are building is something I have seen in many orgs trying to do it internally and fail. PaaS is a hard problem if you want to solve it "reliabily"