Half the TB posts about Fender are "why can't I have a bass with features X, Y, Z, and Q"...
...and the other half of TB posts are "Why do they mess around with a dozen variations on everything, all anyone really wants is just a P or a J."
Fender does have a custom shop. And if that's too expensive, there are a lot of other brands out there.
Most of those people that you speak of want something CUSTOM (special electronics/wiring, custom wood combos, custom colors etc.) I'm simply talking about bolting on parts that Fender already churns out and that already exist in their respective product lines...
and you shouldn't have to go to the customs shop to have them bolt Part B to Part A...it should already exist!