> In 2018, Airbnb began its migration to a service-oriented architecture, as the Ruby on Rails “monorail” started becoming hard to maintain and was a single point of failure.
A monolithic codebase doesn't have to be deployed as a single artifact to be a single point of failure.
There's nothing stopping you from deploying a monolith application across a distributed number of machines in a highly available manner, including making machines favour some types of work (e.g. web workers and background job workers). Nor is there anything stopping you from performing blue-green deployments or A/B testing if you want to interpret single point of failure as a bug is deployed to all machines simultaneously and affects your entire application.
A monolithic codebase doesn't have to be deployed as a single artifact to be a single point of failure.
There's nothing stopping you from deploying a monolith application across a distributed number of machines in a highly available manner, including making machines favour some types of work (e.g. web workers and background job workers). Nor is there anything stopping you from performing blue-green deployments or A/B testing if you want to interpret single point of failure as a bug is deployed to all machines simultaneously and affects your entire application.