After seeing enough of these "alternative internets" to make your eyes water, I have to wonder; at this point, is it even possible to implement these at scale? As well designed as the technologies may be, how could these be possible marketed to the layperson, who is happy with the current infrastructure?

The only recent/ongoing shifts in internet technology are IPv6 and the https push, and they are both built on top of existing technology, and have been extremely logistically challenging to implement. How could a total revamp possibly fare?