Been thinking about such possibilities. With the advent of serverless, what executes a controller action does not need to be a server executing every other controller action in an application.

We don't need to keep two machines alive, one each in two different availability zones to provide the bare minimum uptime. Not if any controller action can quickly be given part of a machine on which to execute. There is no uptime or downtime, other than that of the service administering this fleet of machines.