In Simscape Electrical (or other Simulink toolboxes), the models for Permanent Magnet Synchronous Motors (PMSMs) can indeed start and run without a separate control loop when you use a SVPWM block. This might seem counterintuitive since in the real world, PMSMs are not self-starting due to the synchronous nature of their operation, which requires the magnetic field generated by the stator to be rotating at the same speed as the rotor's magnetic field from the start.
However, the simulation abstracts away some of the real-world complexities. We then need to choose the right model fidelity for the task we have. Model simplification allows users to quickly test and validate certain aspects of motor control systems.
