This is exactly my view, especially with the web apps. If you take a distributed system, the majority of components/microservices will have more than 50% common

This is exactly my view, especially with the web apps. If you take a distributed system, the majority of components/microservices will have more than 50% commonality in behaviour. Therefore you do mostly the same things when you start a new one. Even if code itself might be harder to generate, as even a CRUD app might have specific behaviour, testing it is definitely the same, especially when doing negative scenarios, boundary testing, CRUD operations, etc. I wrote a tool specifically for this purpose, targeted at REST APIs, aiming to automate this repetitive work and let you focus on the tests which are specific to the context.