I don't think it's the communication that's lost, it's the motivation. People love to collaborate, but they don't always want to waste time doing it.

It's the same reason you see 'no AI' repo labels: only by forcing some standard on the community can the 'old way of collaborating' continue to exist.

There will for sure be new ways of collaborating, and walled off gardens like you suggest, where communication stops and everyone just shares some final product.

But, in some cases the product must be understood (or demonstrated) before value can be derived, and so collaboration will still exist.

Desire, and the 'shape' of collaboration has changed greatly though. Why collaboration has changed, is a completely separate issue related to economy and how each of us spends our time.