One could probably take out half the studs in a typical residential wall without affecting the structural integrity of the building; the requrement of having studs every 16" is to allow people to lean on walls without them bending--not because it's necessary to support the weight of the roof or upper floors.
On the other hand, most buildings have many single-point entities whose failure would cause a significant partial or total collapse. Bridges are even worse: a failure of one of the main cables on a suspension bridge could topple the whole thing. Of course, most of the single-point-failure items are rated to withstand loads sufficiently in excess of the loads they'll face that failure is unlikely.
Wall studs are spaced at 16 inches mostly for the convenience of modular wall board which comes in increments convenient for this spacing. As a result many walls have far more strength than needed for carrying loads.
This is not the case with floors and roofs. They are sized more for strength.
For non residential buildings, you can count on the savvy owner to make designers just provide enough strength to meet codes.
But those cables are made of thousands of individual strands fo steel wire so there is redundancy built in. A flaw or break in one wire won't cause the whole cable to fail. Also, the cables eventually do get replaced as part of their maintenance.