I think the OP’s point will be familiar to many NG operators.
Autobrake 3 is often not quite sufficient, and Autobrake MAX is around DOUBLE Autobrake 3 and is quite unfriendly to the pax if not needed.
It would be nice if Boeing had implemented an Autobrake 4 on the 737NG.
But they couldn’t. For the same reason they couldn’t implement a lot of other nice things. Ask the FAA.