Check this out: https://www.dxengineering.com/…/nte-adjustable-ladder-style…
I post this to show how even with mainstream, crappy wire-retention devices like sold by this reputable vendor, they STILL have markup far more than you’d expect, and well within my ability to print a better solution. Who knew this entire “specialty wire management device” industry was operating on such fat markups in low quantities? 