"Uncertainty is a common source of anxiety, resulting in dissatisfaction," is an assumption. When I sign up for a new service, I'm not thinking about outages. Conventional wisdom says that reliable services that are always online would be perceived as being more trustworthy than those which go down. It is a paradox because an occasional outage correctly handled results in greater customer loyalty than if no outage occurs, ever. Yes, there will be tipping point where the inconvenience of too many outages, even if handled well, will outweigh any loyalty gained from recovery.