a) Loose, (unsealed) bearings in wheels.
Some people manage to regrease their own bearings, but they’re in a tiny minority of the population.
A more realistic scenario is someone taking their bike to the lbs because the bearings are grinding against the hub surface. By then it’s too late and the entire wheel gets tossed for recycling. An environmental snafu that shimano and sram need to address.
For most people, the convenience of fit-and-forget components on bikes should be part of the British standards, and loose bearings in wheels should be reserved for pro riders.
b) square-taper bottom brackets.
While we can appreiate the fit-and-forget durability of shimanos sealed bottom brackets, why persist with the square taper?
There’s precious few guarantees in life, but you can be pretty certain of the drive-side crank falling off a a square-taper bottom bracket.
Shimanos octalink system is a far more secure means to attach cranks to the bottom bracket and probably costs the same for shimano to manufacture.
So why do they persist in manufacturing square-taper bottom brackets?
It just ruins the overall cycling experience when someone’s crank falls off or they belatedly discover that they need to replace their wheels because some grit penetrated their hubs.
As a consumer rights/ sale of goods issue, I don’t think that loose bearings and square- taper bottom brackets are truly fit for purpose.