with all the billions being spent on fully self driving cars why doesn't a company build a fake indoor town where it can simulate various driving conditions, we

with all the billions being spent on fully self driving cars why doesn't a company build a fake indoor town where it can simulate various driving conditions, weather, lighting etc and put fake pedestrian everywhere and then have the AI be able to learn in an environment simultaneously more challenging (since you can throw all kinds of shit at it) and forgiving (since mistakes while training aren't hurting people).