The debate about whether AI will reshape software is usually framed as a contest of model quality: better models make better features. That framing hides the real change. The decisive difference between an Al-first platform and a legacy platform with Al bolted on is not how good the model is. It is a question about who, or what, sits at the center of the system and decides what happens next. Classical SaaS was built around a human orchestrator. The software is a deterministic instrument that waits to be operated. Al-first systems move the orchestration function out of the human’s head and into a model-driven core.