You are right, bro. The number of years that a casino company has stayed is not what will determine if they can allow such a huge amount to be staked at once, unless it's something they have allowed from the beginning. I have not used that casino but only pointed it out for OP, and I already told him that the only way to find out is if he practically tries it out by himself. I have tested a few of those casinos, but another thing I have not tried is to stake a huge amount (like the OP mentioned) on a single game.
Any ways you are right to say so, but those casinos that have stayed in business for a whilystill have the better chance of offering higher limits to the player's since most of the games providers who are the sole actors in the amount of bet allowed by players will have been used to them and also worked on some of the feedbacks from player's who have suffered from such limits in bet amount.
So for that sites like stake and other long operating casinos have such development if I am not mistaken.