Often the wear-well factor came thru iteration rather than out of the box - AT&T was famous for doing this, because it did its own remanufacturing and recycling

Often the wear-well factor came thru iteration rather than out of the box - AT&T was famous for doing this, because it did its own remanufacturing and recycling in house - it had literal feedback on how its equipment wore in service - beyond the indirect feedback it got from the field forces doing the repairs.