php server code generated by swagger codegen is too big

I used codegen of Swagger to generate php server code based on openAPI document. The interface is simple and not that much complex. However, the generated code has in total (after downloading all needed dependencies using composer) a size of 1.7 GB.

Is this possible and realistic? This is bigger than the size of a complete OS! Does someone have an explanation?

I understand that adding abstraction layers inbetween results in increasing the size, but anyhow 1.7 GB for a simple REST server is unbelievable and really HUGE.