You have a narrow perspective...there are currently 15 teams with bullpen ERAs less than 4.00, and there were only 3 teams in 2006 that had team bullpen ERAs less than 4.00. There are also 5 teams who currently have team bullpen ERAs less than 3.00, since 1999 there has never been more than 4 teams that low at the end of any season. Many of those season finished without even 1 single team having a team bullpen ERA less than 3.00