> The other reason is that you cannot split up a large established codebase without first understanding it. I have seen large codebases successfully split up, but I have never seen that done by a team that wasn’t already fluent at shipping features inside the large codebase. You simply cannot redesign any non-trivial project (i.e. a project that makes real money) from first-principles.
This resonates. At one former company, there was a clear divide between the people working on the "legacy monolith" in PHP and the "scalable microservices" in Scala/Go. One new Scala team was tasked with extracting permissions management from the monolith into a separate service. Was estimated to take 6-9 months. 18 months later, project was canned without delivering anything. The team was starting from scratch and had no experience working with the current monolith permissions model and could not get it successfully integrated. Every time an integration was attempted they found a new edge case that was totally incompatible with the nice, "clean" model they had created with the new service.
This resonates. At one former company, there was a clear divide between the people working on the "legacy monolith" in PHP and the "scalable microservices" in Scala/Go. One new Scala team was tasked with extracting permissions management from the monolith into a separate service. Was estimated to take 6-9 months. 18 months later, project was canned without delivering anything. The team was starting from scratch and had no experience working with the current monolith permissions model and could not get it successfully integrated. Every time an integration was attempted they found a new edge case that was totally incompatible with the nice, "clean" model they had created with the new service.