Yes, I could set up a private limited company and work through that, paying myself in dividends rather than salary. I know people who do this - mostly in IT, but people like builders and plumbers do this as well. Unfortunately, I don't think it's an option for me - I doubt the University would be willing to go along with this.

But even taking this sort of scheme into account (and assuming one manages to avoid being clobbered by IR35 and the like) it's still true that big corporations and very rich people have far more such opportunities than the rest of us.