These are justified when looking at the truly elite level. You’re looking for fractional improvements that might add up to a watt or two. Aero frames, internal cables, spandex, are all about things that will make a marginal difference at an elite level.

Disc brakes have been a bit of an outlier with extra weight and safety issues brought up by riders. Though it’s easier to internally route cables, and you can stop quicker and more predictably. Maybe the aerodynamic issues of the cables are big enough to switch for the elite riders.