Even so, the number of experts looking at the code will increase if it's open, right? I know the concept of "many eyes makes all bugs shallow" isn't the panacea

Even so, the number of experts looking at the code will increase if it's open, right? I know the concept of "many eyes makes all bugs shallow" isn't the panacea we once thought it was; that still there can be bugs lurking in widely-read sources. But it must be smaller than the number of bugs that exist in code read by a smaller group.