It's been tried a few times. The bottleneck still exists in the last mile of the network. Users simply don't have good enough equipment to reliably handle this amount of streaming data.

Yep, real-world HLS/DASH solutions rely heavily on edge caches; you don't care as much about having your infra in the right region, but POPs are everything.

Netflix famously offers ISPs an appliance.

One of the problems is that even "symmetric" connections are usually not symmetric at all (obviously talking about residential connections here, not DIA).