But it was a fine rant!
Going "realistic" often takes more work and is more difficult than
"designing" a movie. Costumes must be carefully selected, lighting
must be carefully placed, locations must be carefully chosen, camera
angles must be carefully worked on.
Audiences are accustom to seeing things in a movie in a specific way.
You car example is perfect - if you can't see the person in the car that
isn't "realistic" because if you were standing there, looking into the
car, you would see the person in there. The camera needs a little help.
Have the characters where what a character like that would normally wear in that situation and all that.
You're right. You can't just have each actor put on whatever they have
in their closet. What a character would normally wear in that situation
should be carefully thought out. For example, if your character is a college
professor in a small town and you hire an actor whose entire wardrobe
consists of California surf and club attire, you are going to need to get
the clothing a college professor would ware in that situation. And a Berkeley
professor is likely to dress differently than a Harvard one.