It's funny that you're commenting on HN, which is just one of the tools YC uses to capture a global mindshare. Aspiring entrepreneurs around the world now know about YC's track record, so it is kind of hard to justify choosing say Techstars UK or Techpeaks if you also get admitted to YC. The startup ecosystem is indeed not as mature in UK/Europe as it in the Valley, but not for lack of informed, aspiring entrepreneurs, but lack of accelerators and funds that are as reputed as YC.