200 families who are projected, on current trends, to own more wealth than the entire U.K. GDP by 2035.
And no, they do not do more work than the rest of the U.K. put together
You're mixing up wealth and income.
The medium household wealth in the UK is £293,700. Median income is £32,400. So median household wealth is 9 x income.
GDP is a measure of value created in a year. It's effectively the UK's income. That's different to wealth, which is built up over many years (or many generations) - by spending less than you make.
Income - rather than wealth - reflects the value of what you've contributed that year. That will include both actual work, and also getting interest/returns on money you make available to other organisations which they use to operate and create value (you're deferring your own use of that money so they can make value out of it). Capital gains isn't included in income.
You work for the NHS - that's great. The high value of your work is reflected in the £71.1 billion spent on NHS salaries each year (that doesn't include GPs or employees in the Department of Health and Social Care, NHS England etc).
That's 2.7% of the whole of the UK's GDP every year going to the 4.5% of the UK population doing that work.
That doesn't seem out of whack to me. Especially given some of the value in our GDP does have to go to the people providing the money to allow value to be created, not only the people doing the work.