Has there been any situations where DOSP is shown to be effective and complete? They always seems to be a closed source core. I tried DOSP for one of my projec

Has there been any situations where DOSP is shown to be effective and complete? They always seems to be a closed source core. I tried DOSP for one of my projects and it was impossibly hard, because the business and the system was built with closed source assumptions to begin with. Now I just do everything open source from the get-go and it is much easier.