Papers are a conversation as much as anything else.

I agree that these days the tooling makes it much easier to distribute code & data somehow to match up, but there is also a cost/incentive mismatch. Basically to do a decent release of what you are working on and worse, potentially support it, costs time but has no real career value (yet). Which means it's mostly only done by people who are philosophically convinced of its value.

I think this will change over time, at least in some areas, but it won't be quick.