I do understand where you coming from, but every site needs big winners. People wouldn't trust the site if there were no winners. Plus, most of such winners will likely come back for more... you know what that means.
But I don't expect anyone to gamble big today, it's Fri the 13th after all, and many gamblers are pretty superstitious.
IF a site is on minus profit, i think it would
serve as a marketing purposes for the other to come and play in the sites since the sites is legit, i remembered moneypot went up to minus 26 btc , this serves as marketing, sites got more traffic and have recovered since that time
Not really works for crowdfunded sites (with investment option). If the operator takes commission from the amount wagered, he doesn't really have any incentive in rigging the game one way or another.
If the site is on loss, players could take it as indicator that the site is legit, but investors could get suspicious and get the opposite impression. That's what happened to dicebitco.in, one player (likely operator himself) had almost impossible streak of high wins and wiped out most of the investments. That didn't attract masses of new players, but was final blow that killed that site (they had skipping-nonces issue shortly before that).
But most of all, if the site is legit, they don't have any influence on whether the site is currently on profit or loss, so they cannot use it for 'marketing purposes'.