I am not longer a fan of selling links because Google frowns on this but I guess your point could be justified.. I would just be really careful about selling links; if Google does figure out that you are doing so it may come back to bite you.
Nah, I am not a PR addict. But I think that's the reason. I mean what else is there? PR doesn't beat content.
The pr valuable in a sense that people pay attention to it and is a factor people consider when dealing with websites. People with high pr sites don't want to deal with sites that have 0 pr. As said before if you content/product sucks then it's not going to make you money.
Many of the current regulars believe PageRank (PR) is no longer important to Google SERPs. Google started it’s search engine based on PageRank, but over the years they have had to alter their search algorithm to combat those who try to gain higher rankings through understanding how the algorithm works and adapting a websites code etc… to meet those requirements.