Majority of gambling sites now doesnt really accept any investments but there are some which are still accepting like
https://www.bustabit.com/bankroll/change-bankrollWhich no doubt that it do really make profits in long term but dont expect for it to be big but not really that a bad idea.
For totally new casinos that do ask out for funding to build the site then this is where doubts and hesitance do starts.
But there are casinos like Betfury, OWL, Chips, and some others, that have their own house token, holders get a piece of the profit on a daily basis, and some of them have even more features for their tokens! With this feature it's better to start earlier, you get to mine more tokens for less price! The ones who come later need to wager more to get the same amount of tokens...
It's simple, new casinos must offer some great promotions if they wish to attract people! Look at Stake with a $100k price for a daily race, Wolf with $5k... competition in crypto gambling is already crazy, so new casinos must be competitive if they wish to draw our attention! And it's on us do we want to try that new casino with some awesome promotion or will we stick with the old ones!