I'm not a insurance expert, but thanks to good old no fault. Their insurance covers them & yours you. Many people don't give a rats behind what damage they do to you or themselves.
The only thing the dash cam would have been good for is proof needed for injury claim. But maybe if you had a video you could have sued them for your deductible or your out of pocket expense - if worth getting a lawyer for.
Possibly if a video was present the cop might have wrote a ticket if any laws were broken.