You are confusing radar and lidar I think. True solid state automotive lidar is largely still in a research state. Most 'solid state' lidar sensors actually have very tiny moving parts in the form of MEMS assemblies. Even more delicate than a macro mechanical assembly.

But for radar, correct, those modules are available as a commodity for automotive lifescales.

The general problem is that simple, cost effective radar is low precision while expensive, complex lidar is high precision.