Providing lots of generic World Cup information in the lead of each WC article is just taking up precious lead space unnecessarily. Every WC since 1950 is quadrennial. Every WC since 1934 (?) has involved qualifying rounds and finals. Every WC since 1986 has had group and knockout stages. The lead is not a primer on World Cups in general. It's not because we assume the reader knows all this stuff; it's because we give the reader credit for figuring out to click through to FIFA World Cup if he wants to learn more about the tournament.