I would think the starting point there would be to get as many of the GDL archetypes into CKM as possibl. Many are scores / scales. Since many of the Nedap ones are also scores, it would seem worthwhile considering performing a cross-check of some kind e.g. at least the names, to see what the overlap is, and then identify some good ones / highly reusable ones, and translate to EN and propose to CKM.
These archetypes have cost Nedap, Cambio and anyone else who does them hundreds or thousands of hours. So why share them? Well, … good PR etc, as @joostholslag mentioned above. But there is also some enlightened self-interest. If Nedap shares their DEMMI (which I just learned was Morton Mobility Test!) and it gets taken up, then all data in openEHR systems for that test start looking like the Nedap model. Might be good if Nedap has an app that does interesting stuff with this particular data… now it can be used in more places. Same for the 500+ score/scales from Cambio - if at least some of those get into CKM as the accepted version of that scale, then Cambio apps or CDS that know about those data sets will work in a lot of places. And so on for DIPS etc etc.
The big picture: no matter how amazing any one company’s archetype repo is, it’s probably only 5% of medicine. CKM might be ?30% coverage - and it’s already the largest clinical model repo in the world by data point count. But if all those 5% libraries get added together into CKM, then we’re getting serious coverage, and each company gets for free many times its own repository worth of archetypes.
Another thing: there is nothing wrong with charging customers (typically healthcare providers or authorities) for the development work on those archetypes. There is also nothing wrong with telling them you will open source them, and everyone does that - so that they will not get charged anything for the greater number of archetypes already built.