I cannot figure out how you can see that. RPC just adds a "Remote" on top of the "Procedure Call" part, we add a failure mode but the thought process is the same.

As witnessed by many teams, spaghetti happens just as poorly in a distributed monolith as it does in a proper monolith, it just adds latency and makes it harder to debug.

The boundaries you're imagining are not drawn by the technology nor by the separate codebases, they're drawn by the programmers making the calls. And I guarantee you that the average developer with their usual OOP exposure can understand much more easily where to draw decent boundaries following some pattern like Clean/Hexagonal/Onion/Whatever Architecture as opposed to microservices, where it's far more arbitrary to determine the concerns of a microservice, specially when a usecase cuts through previously drawn boundaries.