Genuine question. If the percentage of tax for the wealthy is continuing to go up and if there are always calls for them to pay 'just a little bit more' then at what point does it stop?
Very generally speaking, some of these very wealthy people are not just using their wealth to benefit their families, they are part of the problem affecting the home owning aspirations of the relatively poor. They are "raking it in" through their high rent charges, sometimes with enormous rent empires, leaving the relatively poor no chance of putting savings away for a home owning deposit after paying other essentials.
UK housing has not had a fair supply and demand market for decades, by and large the build rate of new homes has far outstripped demand of a growing UK population, often making house prices rise faster than inflation. But the wealthy have been able to still buy homes to add to their renting empires, further reducing the number of homes available to buy, further freezing out the poor from getting a mortgage while landlords can then shaft them more with increased rents.
This whole situation is similar, but on a larger scale, to how electricity suppliers used to shaft those with pre-pay meters (often the poor) with higher consumption rates than standard meters where we pay by direct debit.
The gap between the wealthy and poor is becoming a chasm, the people doing relatively mundane jobs that make society work rarely earn enough to contribute much Income Tax after getting their minimum wage hourly rate, but money stills needs to be raised to provide goods and services for society... So the relatively wealthy need to accept the burden of more taxation.