As pilots we tend to see things, understandably, from the operational point of view first and the business point of view second.
If Boeing had altered the auto speedbrake design as a direct result of the Cali tragedy (which, from an operational point of view, I think it should have) then it would be tantamount to admitting to a design flaw and leave Boeing exposed to a level of litigation and subsequent adverse publicity that it probably could not afford. As much as I hate the lack of a design change, I can understand why Boeing resisted it.
I am sure the same thing is happening now with the 737 Max, though after 2 accidents and multiple loss of life on a new type for apparently the same reason/design flaw, quite clearly a change has to be made.
The EK521 is very different in that all the information necessary to have avoided the accident was available - though it can certainly be argued that essential operating information was buried deep in the FCOM, not highlighted well enough and not taught and reinforced in either conversion or line training.