You're narrowing down my line of reasoning to a specific example and then disputing it. But you didn't answer to the overall fact that there are central points

You're narrowing down my line of reasoning to a specific example and then disputing it. But you didn't answer to the overall fact that there are central points of failure in most electronic devices/infrastructure that are even more critical than a vacuum cleaner. Yet we still rely on them. That doesn't make the whole "electric" infrastructure "a mess". And BTW not every blackout can be solved with a generator. For instance a city-wide blackout, in regard to streetlamps etc. Also, not everyone can install a generator. Not every landlord allows a generator etc etc. Even if you had a city-specific generator, that can just as well fail. Now, if your not concerned with a backup system failing you shouldn't need to be concerned with Amazon's system failing as they also have multiple backup systems in place.