If Next.js + Vercel is the leader of the production-ready frontend-as-a-service space, why hasn't a similar leader emerged in the backend-as-a-service space?

I would love a clean Vercel-like abstraction on top of standard cloud primitives (functions, queues, events, workflows, etc.) with everything wired up nicely and focused on developer experience. It just seems like AWS is so configuration heavy that it is ripe for a Vercel-for-backend to emerge.

Does anyone know of an existing open source framework + hosted cloud platform that is a one-stop-shop for writing a production-ready backend in the vein of Next.js + Vercel?