To answer your question, yes there are many “turn key casinos”. Basically, think of a provider and go to their website. They handle everything from payment to new games going through customer service. All you need to do is advertise.
BUT it’s easier said than done. First of all you need a lot of money. I don’t know about casinos but if I remember correctly, for poker rooms you need to pay them 2k whether or not you make any money, each month. At least that is what the Costa Del Poker owner was saying. Then you need to advertize which costs a lot since there are a million competitors out there.
So anyway, I hoipe that answers your question a bit.