Because the economy doesn't just magically grow or shrink. It grows when entrepreneurs drive the growth with new and expanding businesses or technologists invent transformative technologies. But those people will earn an outsize chunk of the new value they create, otherwise they wouldn't take the risk trying to create the new value.

Growth comes from economic freedom, and economic freedom rewards people who create value. The only way to have the 1% not change and everyone else go up 5% would be crushing controls and oppression of the top 1%, but that lack of economic freedom would make the more general growth impossible. You would just get flight of capital and brain drain to a more economically free country.

People are inherently unequal in drive, intelligence, patience, work ethic, everything. The more economic freedom there is, the more unequal outcomes will be. The less economic freedom there is, the less unequal outcomes could potentially be, but there will be no growth or prosperity. So it seems the two choices are that we can have growth, but some people will gain more than others, or we can stagnate or shrink. I think it's magical thinking that we can just tax the successful into Oblivion and they will just keep working hard and nothing will go wrong.