Maybe for the clients as well as they're getting better prices.
Market makers lose with toxic flow (on balance), retail is not toxic and never will be so bid-offer prices ONLY for retail can be tighter/better than for large potentially toxic customers/flow.
Selling flow to Citadel is therefore good for the small clients.
Go back to 1/8th and 1/4 and the old floor for fills versus what retail has now.