I use the term similar to who it's used for non-profit. The orgs I'm involved with are almost exclusively not involved in the actual standards creation.
If the secretariats were to shut down tomorrow I'd say the actual work on the standards could continue without anyone noticing.
There is a reason that at least the EU is considering modernizing the system. https://single-market-economy.ec.europa.eu/consultations/pub...
ISO, CEN, CENELEC, ETSI are stuck very much in the past.
So yes. Overhead.
BSI Group, for example, paid 26.1% tax (25% corporation tax plus some other stuff) according to its 2025 financial statement.
In my direct experience, the people who write the standard texts get a room to sit in, power for laptops, a whiteboard, and tea/coffee and biscuits, a few days per year.