Of course we have no idea of their personal circumstances. Some people are willing and able to spend £thousands on their cars, including insurance. Some businesses allow their staff to choose a leased car with insurance included. Of course there are some people who cheat, either by not having insurance at all, or lying to the insurance company that a parent is the main driver and they are a named extra. No doubt there are other ways I haven't thought of.
I should add that I do not recommend any of the above. If you take the risk, you may well have to pay the consequences. Incidentally, I am still paying for my daughter's insurance, and it has now dropped to a manageable £300.