So we can agree that capitalism produces vast wealth and vast inequality. You believe the inequallity is purely the result of the quantum of goods and services, whereas I (and Picketty) see it as an inherent feature of the system. But that difference doesn't matter too much since we agree that capitalism is productively superior and in practice can result in vast inequality.
But I see that inequality (and the other ills resulting from the capitalist system) as arising from its unrestrained operation when unregulated or poorly regulated.
You avoid confronting the issue of regulation and (what I see as) a societal duty to ameliorate the bad effects of capitalism by clinging to the fiction that all transactions are voluntary and markets are perfectly efficient.
This story may give you comfort, but it ignores the fact that even heavily regulated markets do not operate with perfect efficiency, and there are vast differentials in resources, power, and the ability to capture and monopolise 'free goods'. Unregulated markets are worse in these respects.
What I actually suggested is that unregulated or poorly regulated capitalism causes inequality and misery. It isn't too hard to find examples. Sweatshops, child labour and prostitution, poorhouses, a third of young women in London surviving by prostitution, Flint Michigan, Amazon Rainforests, industrial scale slavery, Bhopal etc etc.
You may like to Google "The Spirit Level" if you want to investigate how inequality in itself causes ill health and unhappiness - but be warned - it may well make you feel uncomfortable.