Those people, in those positions, probably don't need much in the way of process. If you really can just sit down with the owner of the business, hash things out with them, and then go build something that does what they need then you're golden. And guess what, you're probably doing agile without even knowing it, because agile is attempting to reproduce that in organisations where you can't just put a single developer and a the CEO in a room and expect that to happen.
That's surprisingly common across the field. Most developers work on small teams doing small but often very long lived projects. Code staying in production for 30 years is surprisingly common outside of SV.