> which effectively means you work most of the year for the tax man and not yourself

That would be true, if we lived in a world where your gross salary corresponded linearly to the amount of work you did. In that world, the hardest-working CEO would make 3x (maybe in some extreme cases 5x) what the laziest server made. But instead we live in a world where the "successful" make 100x-1000x, because that money isn't coming from their effort, it's coming from a combination of government subsidies (you may not be using the NHS, but the poor people who make your job possible certaintly are) and extreme power imbalances in market conditions that allow them to pay the people on the ground creating the value very little.