The money paid in bonuses could reduce bank charges, increase interest paid, pay ordinary bank workers more, reduce interest charged on business loans (or just lend more - there might be more entrepreneurs if these capitalist banks weren't so risk-averse). Money circulates in the economy, in the poorer 95% of the population, which is better for the economy.
Yeah meanwhile in your master plan there would be a massive black hole in funding the NHS, roads schools,defence, benefits etc.
You have not yet grasped that the uk needs a certain amount of money to function and the top 5 percent pay nearly half of their wages over and half of the income tax take needed in the uk. The more people earn the more tax we get particularly if administered under paye. It's a good thing for the exchequer not a bad thing.