History is written by the victors, and unfortunately Sanger decided to instead focus on Nupedia, which was more focused on "experts" writing the articles. Ultimately it seems that Sanger didn't truly believe in the core underlying idea of Wikipedia, which is that allowing anyone to write/edit without any reputation or credentials (or even an account!) eventually leads to a good outcome. It's counter-intuitive to some degree that the noise of allowing the "unwashed masses" to contribute is outweighed by the ease of attracting new contributors combined with the decentralized, crowd-sourced corrections of the community.