Unfortunately, there is basically one way to make an ASIC.  It needs x amount of transistors and registerable cache in a certain ratio to run bitcoin operations a certain way and certain power levels obtain certain acceptable or unacceptable heat dissipations.  If you add double the memory that you need to run bitcoin operations, that just means you wasted money in the design so they're all actually going to be structured extremely similarly.  They obviously didn't invent a new way to actually build the chips' internals themselves, that's up to the Asian factories, so they're all just reinventing the wheel exactly the same way separate from each other.

This isn't like making an airplane where one guy does 2 wings and a propeller and the other does a jet engine.  It's more like making ice cubes, lol.  You hold water in something and drop it below 32F or you don't end up with ice