Pegs, seat, and handlebars: you said all are available in the aftermarket. Yes they are, and I understand what you mean about a factory installed option maybe not fitting you. No offense intended, but couldn't Honda add those so at least they fit SOMEONE, rather than NOBODY? LOL!! Look, I understands from riding Road Kings long enough that changing a seat is not only desired....it's IMPERATIVE!! LOL!! BTW, you have to change handlebars on the Road King too. They don't fit anybody.Happily all those are easily fixable in the accessories aftermarket.
And in a way I am kind of glad they are not standard options, if they were would they be in a shape/location that would fit me. Would the designers place the forward pegs far enough out for me with a 36" inseam, or the seat sculpted for my size derriere. Handlebars, grips, etc... Why pay the factory for upgrades that won't work for me?
But factory cruise is definitely a one-size fits all option.
Pegs, no that's another matter. THat is something that is SOOO personal I don't see how any manufacturer would be able to set them up for a one-size fits all position.