I agree. I speculate that IoT applications, from where the growth and volume would come from would mostly be needing "low power" and hence data rates would be lower. The focus should be low power and not speed, I think. In that context I don't know which IoT market is on radar of PCI SIG, where they see good growth. May be, for the servers, which would have large volume of data due to so many devices connected and that is where >32Gbps speed would be helpful?
I think you hit it right on the head. Each device may only need a small amount of data but will billions of them, servers might be overloaded. In the end, IoT devices could consume more aggregate bandwidth than is needed for video, simply by the sheer numbers. Give it 20 years or so.
In gerenral, 10000 of IOTs will be connected to a server (Low-mid end). If we can increase the bandwidth and deploy high end servers, we can connect 0.1million to 1 million of IOTs per server. This will be huge saving from data centers perspective.