They want LOSING players (as always) or player who won’t take a payout for a while.
Any bonus tossed out there is going to be designed to tie up the average player to keep them from cashing. No one wants to give known players who can bust out a 10x roll in a week a bonus.
Not only are funds harder to bring in - but books are slammed with payout request. No bonus = winner players being able to cash out immediately (which they will do after each big win).
Even if 35-40% of players seek a payout - it creates a run on the bank situation as processors can’t keep up with all the request at once. Already has a book tell me it would be 48-72 hours to process my payout today - usually handled within 8 hours. It’s just the limited capacity of the few processors. They are designed to take in 10x what they pay out.