I completely agree with roc that once you start thinking about it, there are just too many holes in the argument for prioritising on type. "Type" can just be a synonym for "provider". There will be nothing to prevent carriers to push new protocols to a non-priority "type", if they don't pay up.
If voip calls get priority, what prevents me from writing a torrent protocol over voip? That would just be a waste of bandwidth. Prioritising will set off a never-ending arms race.
Emergent complexity is not "random", although it can be based on elements of randomness.
Nature is an example of a massively complex system that has evolved on elements of randomness, but the system itself is by no means random. And there's no way that it could have been designed with a "well thought out procedure".
The key is to make the entire case moot. That can be done with a combination of software engineering and increasing bandwidth.
the challenge is how do you promote developers to build bandwidth efficient systems, as it seems bandwidth is now a distant thought in the minds of most developers.