i do not want to mention sites but on others sites with levels similar to this, they give you close to 0.05btc for hitting ranks similar to the delta. which is a 1000000 dollar wager. i was given 400 dollars for wagering that much in one of the sites last week. they also give me weekly and monthly bonuses with outh minor bonu. i am not saying wolf should give all that, but they neeed to give something to guys that have wagered 1000000 dollars. sometimes i regret wagering so much on wolfbet because if i had done that on the other site, i will be gaining close to 0.1btc as bonus by now for wagering this much.
I believe I know the site you are referring to, but in case of bonuses then I also believe that every site has their own budget for it.
There are also some bigger site than wolfbet but has no similar bonuses as what you are referring to.
All in all, it is all about casino's preferences on what they can give back to their players. I understand you are suggesting for the good of both the site and players.
So wolfbet may consider it once they think that such bonuses will give good effect to them.
It is not really a budget thing because let's face it if someone plays that much, they will most likely lose money to you anyway; which is why you should have some of it saved somewhere to give them back. If a person wagers 1 million dollars on a casino, with 1% house edge that is around 10 thousand dollars lost, and that is just the average, sure you could lose more or you could even profit, but the average lost is 10k dollars.
If you give just half of that back you would be loved, if you give quarter of it back you would be liked and if you give 1/10th of it back you will be appreciated. So, it is not really impossible to do these.