Actually, many of the examples you list would have huge problems scaling to a planet wide intelligence, but that's a side issue.

The space in algorithm land in which practical universal intelligence lies requires high connectivity. It is not unique in this - many algorithms require this. Ultimately it can probably be derived back from the 3D structure of the universe itself.

Going from on-chip CPU access to off-chip Memory access to disk access to remote internet access is a series of massive exponential drops in bandwidth and related increases in latency which severely limit scalability of all big interesting distributed algorithms.