Comment by paulgb

This is a sweeping generalization to make, and I think you underestimate how easy it is to achieve redundancy with modern tools these days.

My company uses redundant services because we like to deploy frequently, and our customers notice if our API breaks while the service is restarted. Running the service redundantly allows us to do rolling deploys while continuing to serve our API. It’s also saved us from downtime when a service encounters a weird code path and crashes.