The scale becomes not quite as impressive if you consider that those thousands or tens of thousands of engineers also maintain hundreds more services in vastly more complex scenarios because they need to cover many more use cases than yours. Most companies don't need to run everything AWS has to offer, so they wouldn't need to handle all of that complexity.

Individual AZs have significantly worse uptime than any DC I've ever worked with. They are very reliable, if you are multi-region - and you hire a small army of consultants.