You took the words out of my mouth. In the movies I watch, the rich people always have a stable of cars and employ their own chauffeur. However, it might be financially wiser to hire a chauffeur from an outside company that provides the car. I guess you’d have to “do the math” to determine that.
First thing is that the truly wealthy can negotiate their own terms with an insurer.
For less beings who may still own a small fleet, there is “Small fleet” insurance. Designed for a small business, but easily adapted to a family. In this type of insurance, the onus is on the owner (or their representative) to establish that the driver is properly licenced, and the policy would cover anyone driving the vehicle with permission. Although there may be caveats like a minimum age or years of experience for example.
If permission was not given the rules for a stolen vehicle would apply .