I'd rather fix up this existing system then day dream about a glorious socialist revolution that always seems to end in blood.
But even if we overlook his inherent bias, he was just plain wrong. He wrote that capitalism had reached its final stage through imperialism, and that, as you said, state capture via financial oligarchy was inevitable. That was over 100 years ago, and history has produced welfare states, labor protections, financial regulation, the SEC, Germany's codetermination laws, even the Nordic social democracies. None of those should be possible under Lenin's framework for capitalism.
(Disclaimer: I'm all for common sense regulation of capitalism.)