I guess bankroll management doesnt have any effect on bankruptcy
Wrong, bankroll management is a must. A proper kelly criterion should be followed and this is to ensure a high roller doesnt break the house in few split of bet thus this will be limiting the house's losses as well.
their bankroll depends on the wagered, the more wagered the site get the most income they get
Wrong, although the house has the edge over for the long run but it is not a guarantee that they house will keep on winning with the more people wagering there as there will be always a day or two where the house is completely out of luck so purely depends on the wagered status isnt right at all
and with a little development I think they wont be bankrupt
Wrong again, a site that put in poor development will not attract any player. Just take a look at how many poorly developed gambling site in this board that dont attract any player at all. Basically they just put their site on launch here and hope for the best which wont work here as there are alot more far better sites in almost every aspect
References :
Minidice : https://bitcointalksearch.org/topic/minidicein-20000-bets-made-weekly-giveaways-social-community-dice-1091286
Doodledice : https://bitcointalksearch.org/topic/doodledicedottk-new-dice-site-1104611
PatDice : https://bitcointalksearch.org/topic/patdice-simple-to-the-point-dice-site-1109238
SawDice : https://bitcointalksearch.org/topic/sawdice-the-new-age-of-dice-lets-play-a-game-1064019
CrimeDice : https://bitcointalksearch.org/topic/crimedice-smartphonecomputer-all-countries-faucet-1083359 ( and alot more, just hit the search button )
Depends on how bankrupt goes that is a way of going bankrupt. Otherwise it is very difficult to get a casino bankrupt. Slightest chance of betting big and getting it all but usually there is a max win and you can not just hope to get lucky at that level. 
