Hello Si,
Although I would love to agree that XTR and Pimped builds are the way to go… I think that the bulk of any bike builders and sellers will sell the standard specs much more, and this will be the bread and butter of any business.
As you have pointed out, you have built some bikes, but mostly small items. I think to appeal to more people, there has to be value builds available, especially with the quality shown in the deore, slx and XT levels of kit. To make the brand exotix, there can still be the pimped builds available, but for people on a budget, they will be happy with the quality frame and possibly wheels, with quite standard spec, especially if you bulk buy the groups and offer good value builds… This kit can then be upgraded and customisedwith time…
Just me ranting on of course!