Do you think that those old techniques will eventually become important again? I remember reading somewhere that the reason that Google doesn't like query strings in URLs (despite its ability to correctly parse them) is because in infinitely large dynamic sites, the spiders and crawlers tend to get stuck in infinite loops reaching the same pages over and over again. I'm sure that Google has implemented algorithms into its spiders similar to BGP (the way that network packets travel through various routers of the Internet to reach their destination, without getting lost in loops).
So you're saying that PR is becoming devalued in the newer SE algorithms? Does this mean that it is not money efficient to spend money on PR and backlinks right now? Isn't PR Google's trademark search algorithm? I would think that Google would simply just make it consistantly harder to obtain a high PR.
Perhaps if Google rotated the weight of each constituent of its search algorithm, it will ensure that high ranking sites have a bit of everything.