Collaboration is terrific and a great foundation.
I think we're past the point where we should be getting excited about seeing collaboration in our own team(s). It's time to applaud and support collaboration between teams - thanking those who join our journey or who invite us to join theirs.
Real life - you and your doctor should be collaborating on your health. When the doctor sends you to a specialist; often the specialist acts like it's a new or different team into which you're being allowed. Not so. It's one team. Not only should the specialist send your doctor a copy of their findings but you should tell the doctor how you were/were not treated appropriately.
Real life - you and your team work on a project. You go to a specialist team for a piece you can't do in-house or in your division. It needs to be collaborative. Ownership of delivering a good result did not cease when you included more people from elsewhere. Nor does it mean that the new players are not now responsible for good results.
The quickest way to get to collaboration is ask for and acknowledge it - good and bad. Applaud partners loudly. Offer our own teams. Ensure feedback and ownership is discussed. Collaboration is both habit and process - both of which need to be deliberately done. Thoughts?