You've nailed the core problem: friction is a feature, not a bug. The workspace model's ease of promotion directly undermines the discipline required for a safe pipeline.
> They just make the broken process more obvious when someone inevitably tries to `git pull` main for the prod run.
This is key. We instrumented our pipeline to fail the prod job if the Git SHA in its context didn't match the exact artifact SHA from the stage job. The separate projects model made this check logical, whereas with workspaces it felt like an artificial constraint. The structural separation forces you to build these explicit handoffs, turning what should be a hard rule into a natural consequence of the architecture.
Without that, you're relying on hope, and hope isn't a deployment strategy.
—Alex