I think for each family they make this decision based on their needs as a family.
Our daughter did not need her own car as a teen or in college so if she needed a ride we discussed whether she would use my car or if I would be able to take and pick her up.
BUT she had quite a few friends that needed a car for many different reasons.
Families where both parents worked full time and their children were extremely active in all sorts of activities and or their teens worked after school or during the summer. .
Families that had also younger children so the older ones drove these siblings to school and to some after school activities because both parents worked full time.
Most of the kids we know are in advanced classes as well as after school activities, so they are pretty responsible kids,
Some of them were able to work a little bit, but most could not work while in full time school taking all advanced or AP classes as well as play sports, or be in theater, Band, Orchestra.. etc..
So the parents either gave them the use of the old family car and the parents purchased new cars for themselves. or They purchased used cars for these teens to use.
My nephews father gave him the old family truck and my nephew was to earn money for the gas and insurance, but that did not last long, sine my nephew was in every sport with training, practices, games and expected to take his younger sister to and from school. He just could not find a job because of his schedule. In the summer he would take on the jobs he could find, but it did not bring in much money.
These other teens did take on some baby sitting, some very part time or seasonal jobs etc.
In our family our daughter knew to never text or talk on the phone while driving. She learned this from me. I NEVER am on the phone while driving. I find a spot and pull over. Even if I am receiving a call, I will not answer. Never have. I am just not coordinated or capable of doing this.
Plus once we had a classmates mother killed in an accident because of a driver that was texting, we knew this was never going to work for us.
Our daughter did babysit, she worked for my business and did some tutoring, so she had money, but I did not make her pay for the gas.
I did give her money when her friends drove. Many of them were on very limited budgets, so I would slip $10 to $20. to our daughter to give these friends for gas. Remember this was during the time that gas prices were really high.
We paid for the insurance. We still do, but our daughter still does not own a car, she does not need one. She lives where public transportation is excellent.
So you as a family need to come up with what you need, and what you think your child can handle.
Be realistic. You know your child the best. Give them expectations and come up with consequences, but also know needs do change very quickly, so be prepared to deal with this.