They've had some great players over the years (Brand, Irving, Boozer, etc.), but also some colossal disappointments. William Avery, Danny Ferry, Chris Burgess, Bobby Hurley, Trajan Langdon, etc. - as well as some of the guys you've listed.
I guess that just comes with a large sampling of players - the good, the bad, and the ugly. That said, isn't it amazing the amount of guys who played for Cal that actually made something of themselves? For every Marquis Teague or Andrew Harrison who didn't quite make a successful NBA transition, there's 5 or 6 guys making real movement amongst the NBA's top 150 rankings.