I understand why you think this way! It's an obvious approach, where there's a bunch of stuff that needs to be done and it's the same everywhere. Why not just have a framework that handles it all for you? It's so clear!
It's perhaps possible that many of the requirements of GDPR are beyond the scope of what any kind of framework or code pattern or generator might be reasonably expected to handle. Code cannot readily become a Data Protection Officer or respond to inbound requests. Code cannot address the need to identify and inform users affected by any breach. Code will likely struggle to do the vendor assurance required of all your Data Processors.
You're absolutely right! There's excellent reason to have the technical requirements handled for you by a framework so you can focus on the important parts of your business. It's just perhaps possible that this could be less than the whole of GDPR.