I think it's also having deeper expertise than is available even for that $1.25m/year. In a previous life, we paid perhaps $25k to a postgres consultancy that

I think it's also having deeper expertise than is available even for that $1.25m/year. In a previous life, we paid perhaps $25k to a postgres consultancy that did support. They employed some of the core devs, and their promise was that you could escalate to a core dev within perhaps 24h. My employer hit a very weird performance regression when a database crossed a boundary size and having that deep expertise on call to diagnose, figure out a short-term fix, and help get a long-term fix deployed was invaluable and worth every penny. The type of people who have millions of dollars of hardware under management pay for support so they can get super deep expertise on hand when they need it.