Comment by verdverm

yup, and while they are fixed, it amounts to a more complicated code flow to reason about compared to you're typical REST handler

Seriously though, you can pretty much map GraphQL queries and resolvers onto JSONSchema and functions however you like. Resolvers are conceptually close to calling a function in a REST handler with more overhead

I suspect the companies that see ROI from GraphQL would have found it with many other options, and it was more likely about rolling out a standard way of doing things