Can't agree with the "Younger, nerdier founders" section.
It's like any other long tail, in this case the prototypical founder (late 20', single, technical guy) will not be as common - it'll become a more-diverse population. There will be younger founders and there will be older founders, too. Nerdier, and hipper. Etc.
For example, I'm a 40 yo front-end developer (started in 1995 building interactive apps at ESPN). I'm now starting a company, doing all the backend development too, thanks to Ruby on Rails. This was never available to me before 2006, really.
My bet - the trend will be away from the core developers, as the back end tools become commoditized and packaged, and the prized employees will become the designers - UI and graphical. Brands and positioning will start to play a larger part, and these contributors will have the most to say about this part of the company. I predict the trend will go away from the technical, as people will need to wear many hats in a small company.
As for the young, I don't believe they have an advantage in a crowded startup environment. The lucky bet, or obvious missing younger-demographic website will be created by the kids, but this will happen less and less as the low-hanging fruit is gobbled up. Instead, I think the older (or rather experienced) will have an advantage in a crowded startup world. Here, it'll be the niche positioning, establishing business relationships, and pursuing effective growth strategies that will make the difference.