Good analogy, and dealerships offer 'trims' of cars - what accessories it's packaged with (e.g.: leather interior, fancy wheels). On a BP/W setup, integrated weight and trim weight pockets, more easily adjustable to fit webbing, and such might also make offering 2 or 3 pre-configured options worthwhile.
And this is part of what frustrates divers considering it. Most divers have never heard of 'Freedom plates' (which were a scarce supply item with a lengthly waiting list when I was looking) or VDH, and you'd have to get the BP and wing from 2 different sources, maybe with a lengthy wait, then what are the odds the LDS guy will web it up for you when you probably didn't buy those things from him? And if you don't get the much-praised Freedom plate, and that VDH Argonaut wing...are you settling for inferior gear? Cue FUD - Fear, Uncertainly, Doubt.
Or...walk into your LDS, try a Hydros on, like the fit, the sales guy talks it up and you feel good about it, it's a strong brand name product, and you walk out happy that same day.
i guess that's why i have both. probably also why i have drawers and drawers and storage bins and closets full of DSMB's, reels, regulators, gloves, boots, knives, oh dear lord.