Some places don’t require insurance. Like in Virginia, you can pay the DMV $500 for the “uninsured motorists fee” and legally be able to drive a vehicle without a loan/lien. But yea, for the most part this applies.
A rare case of the movie being better than the book, although in the book, he's an insurance salesman who hates the industry and its racket so much, that he's willing to commit murder just to get back at the insurance company and take them for a shitload of money.