My experience was with diffing London and Singapore. It wasn't like London was in any way magical, but there was a night and day difference in the quality of technical interviews.
In Singapore if you previously worked at Google you were golden even if you were a goddamn moron and technical tests were done incredibly badly or not at all. I could see why people didn't improve their technical skills and why expert beginners were omnipresent. Nobody was going to reward them for it.
In London that sort of thing exists too but companies that interview on merit rather than pedigree did at least exist and weren't extremely uncommon.
I have limited experience of SF but I expect it is more like London than Singapore.