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.