There are many successful entrepreneurs in Silicon Valley and elsewhere who would be great startup advisors and inspiration leaders. If they decided to start YC clones I don't see why they couldn't attract great talent. They may even be more successful than YC at generating high returns on their investment. Luck plays a huge factor in startup success, after all...
So I think the key to success for YC is not the incubation aspect nor the micro-loan aspect (both of which exist outside of YC). I think the key here is that the YC'er are encouraged to view themselves as the ultimate "surrogate" customers, that they should lead the charge and they have the right to because they are both technologists (i.e, hackers) and representative of their generation.
For example, why not a 4 month boot camp preceded by a 1 month crash course in business, presentation skills, etc. I'm not saying this is a better implementation, only that if the clones thought for themselves, they'd be doing more interesting things, which would tell me they were smarter and actually people I'd want to learn from. I'm afraid to take creative advice from someone whose big innovation is copying YC. I think YC's model is better, and it may be a good thing for it to spread, but none of the clones I peeked at have impressed me much so far.
In reference to the web 2.0 genre, or hashed out in other models as well? The cost of starting a company is falling in other sectors as well...