There are a lot of measurements that are not consistent or even close from bass to bass, so I do see how this is something that plenty of bassists gravitate towards. If you can have at least one consistent landmark on an otherwise unfamiliar instrument especially when string length and as a result the distance between intervals can be significant, it gives a lot of people a sense of security. Maybe that's a crutch, maybe it isn't.
I am guessing there are nature/nurture reasons behind it, but we often make positive associations with things that are familiar, and are hesitant to do the same with the unfamiliar. I am not allowed to make coleslaw after the red cabbage incident of 2012, because that is not how it is supposed to be done. Sorry Grandpa. Getting back to bass, when shopping for an instrument or a bow, we have a tendency to feel most comfortable on something that sounds/plays similar to what we are currently using, even if that isn't the best option. We also have a hard time describing what makes one better than the other, because usually it "just is" or "just isn't". I have a bass that is a D and a bit neck, which makes playing a D or Eb neck a mental exercise for myself. Plenty of colleagues have picked up the bass and said something along the lines of "that's odd" and often don't have much more to say about it because that seems to be fairly jarring. I'm guessing the 5ths doesn't help either.
From a making perspective you want to make instruments that people want to play, because those are the instruments you can sell. Ignoring the math/physics that Arnold and others know significantly better than I, if they made a wonderful bass that sounds great with phenomenal craftsmanship that happened to have a Db or E neck, they would have a horrible time trying to sell that instrument. This is also likely why some makers offer to make D or Eb necks when someone commissions an instrument, because if they are used to one and receive the other, chances are they aren't going to be happy about it. I know I am going to have to make a choice with my next bass because if it is a modern instrument I am not going to expect someone to make a "D and a bit" neck for me.
It seems like D necks are becoming more of a North American "standard" than Eb? Is that a trend that makers/dealers are noticing? Other than player preference, is there one that is better from a structural/acoustic perspective?
