It's an interesting concept but the timing is probably too early. If more people had reliable low latency gigabit or ideally 10gbit throughput, then it might start to approach feasibility. There's other blockers too, but that springs to mind immediately.

It's cool to imagine a planet wide neural network interconnected with fiber - the nervous system of a planetary intelligence. But perhaps mushrooms do that already (Alpha Centauri ever relevant).

Relevant: Why Switzerland has 25 Gbit internet and America doesn't https://news.ycombinator.com/item?id=47652400

Too early too in that later (hopefully) each node can serve a full model so it is then a simpler share tit for tat of complete models.

Too early? the project has been going for years now...