People not paying income tax and national insurance - they're classified as contractors, so technically they're responsible for their own deductions, but I'd be very surprised if many of them are actually paying anything.
That's what I was thinking of, but it's probably also that they simply aren't paying as much in wages.
The older companies at least pay minimum wage + overtime when needed.
Makes a lot of sense. I didn't think about the forgone taxes. Probably quite significant.