It is not merely capitalism, it is much deeper than that: human nature itself, which is prone to corruption and greed. And elites in all economic and political systems (including the "socialist paradise") look after themselves instead of common folk.
"Human nature itself, which is prone to competitive ambition". Competitive and ambitious individuals will use corruption to feed their greed if so allowed (by social /ethical/ legal standards). It is the preponderance of competitive and ambitious individuals in all races of our species that has brought us to absolute global dominance. It will also, probably, be our downfall.
If you take a 2 -3 million year view on Homo Sapiens from a million years hence, I suspect our super-size brain and highly developed 'id' and 'ego' will be seen as an evolutionary dead-end.
