I think the fundamental problem, in engineering terms, is that most cloud deployments effectively wire together cloud components serially.

Your LB may have some nines, your individual vms (or set of vms in a region) may have some nines, your data store may have some nines, but if all of them aren't working together it's unlikely your business will be up.

This is inherently customer-dependent and yet it's super predictable (nobody only uses a lb).