In the past, YC was very specific about moving founders to bay area and it was willing to reject the ones who can't. The reasoning was that the downsides of not being in valley overweighs missing out on otherwise good startups. Now I hear from YC partners, S20 Demo Day was more successful than previous batches. Did all the downsides suddenly disappear? What are the downsides and which ones still exist?
Explaining them would help YC applicants to make informed decision. Otherwise, such claim sounds salesy and too good to be true.
As for the latest batch, others have commented and I've noticed that the kinds of companies YC chose last time seems to have a different focus than previous rounds. Notably, there's a heavy emphasis on dev tools and, to my way of thinking, more companies with quick go-to-market products and fewer moonshots. Perhaps the apparent changes in YC's selection criteria also contributed to their feeling that this batch was "more successful."
Personally, judging from the "me, too" nature of many of the accepted companies in the last round, I find it hard to believe that many (any?) unicorns will come out of choosing the low-hanging fruit. It remains to be seen how these companies will be valued going forward or if their products will succeed in the marketplace, and those will be better indications of the success of the overall batch than any press release.