Nu, nothing's certain, but buying stock does presumably have a positive expected value.

Touching the capital, you can reframe the question as "Buy casino bonds" or "invest in a casino IPO. Besides, even when buying stock from an existing investor, you are sending a signal of the value of that stock - so many mills higher than what the next guy in line would have paid - and that provides working capital in the form of the value of the self-owned stocks, against which the casino can borrow.