Earlier quoted context omitted.
This is correct. They still do this. They are the only ones. They go beyond just "hey, I know of a database that could handle that size" to "why are you storing this here? this is PII, this is analytical data, this is business data, here's a proposal for doing this with open source at scale". It's not just "buy our product". They go above and beyond the needs of the product to the needs of the customer, like you said…
So they're a pure consultancy firm, competing with those infatuated by the write-once-sell-many economics of software.
Linux Kernel, Various JBoss Software (Keycloak is cool), OpenShift, OpenStack, Kubernetes, and more [1]