Tyler Cowen says no intelligent left-winger could agree with this:
Redistribution of wealth has some role in maintaining a stable democracy and preventing starvation. But the power of wealth redistribution to produce net value is quite limited. The power of wealth creation to produce net value is extraordinary...We should be putting our resources, including our advocacy and our intellectual resources, into wealth creation as much as we can.
One reason we can't agree with it is that it might be a false dichotomy. There's some evidence that inequality is bad for growth, and so redistribution might help the wealth creation process. See for example this paper (whence the chart) or this pdf. There's also evidence that inequality is bad for growth in both rural India and China (pdf).
Of course, the evidence isn't all one way. This paper (pdf) finds a positive relationship between inequality and subsequent growth in US cities. And this pdf finds that any change in inequality (up or down) hurts growth. And this pdf finds that it's only inequality after redistribution that's bad for growth.
Nevertheless, it's worth considering the possible mechanisms through which inequality can hurt wealth creation, for example:
1. Poverty causes credit constraints. This stops the poor investing in businesses or education; the low aspirations caused by poverty can have the same effect.
2. Inequality can create the threat of redistribution which can blunt incentives to invest. Or it can lead to state interventions - such as the minimum wage - that harm wealth creation. The backlash against wealth-creating processes such as globalization, offshoring and private equity in the UK and US are founded in the view that they create inequality. If we had better redistribution mechanisms (say, a basic income) such backlashed would be reduced, and the wealth creation process enhanced.
3. Equality can encourage investment in infrastructure, such as transport or secure property rights, that helps growth - because such infrastructure is seen to benefit all, not just the rich.
There's something else I'd add. One reason why wealth creation is a good thing is that it fosters increased respect for liberty and autonomy - perhaps through Maslow's hierarchy of needs. But this also implies that a group of people who feel poor won't respect freedom so much. So perhaps more egalitarian societies are more likely to respect freedom. Are civil and social liberties really less secure in egalitarian northern Europe than in the more inegalitarian US?