My comment isn't about how much they can release. It's about how much of the released people can buy. Oversaturating a market is not a good thing.
I feel a lot of folks have a backlog of "things to buy" that might be rearranged by releases, but not eliminated.
I personally got into Primaris late in the cycle and paint slowly. I've got the Primaris half of Dark Imperium and Shadowspear, a box of Reivers, box of Hellblasters, box of Aggressors, all the Lieutenant models, the 500th Captain and the Store Birthday Captain.
I still plan to buy the E2B kits, a box each of everything from the first release wave I don't yet own, and the new Repulsor. I know i won't be able to buy all of that before the next wave comes out, but I will buy it eventually.
There are certainly people who buy everything at once when it's released, but just as many who slow burn instead.
Of course, I may have missed your point entirely.
-- "To locate, close with, and destroy the enemy by fire and maneuver, and to repel the enemy assault by fire and close combat."