How do we tell whether autonomous cars are actually making progress? Is this a big bang final reveal, or is it possible to tell that every quarter, something

How do we tell whether autonomous cars are actually making progress? Is this a big bang final reveal, or is it possible to tell that every quarter, something on the way to full autonomy is developing? It seems that these spinoffs and acquisitions of Lidar companies, etc. all say they solve a piece of the puzzle, but it still seems no closer to a real system.